Theories

This article will archive all of the Published and Fan Theories that exist for the show Heroes.

Andrews, Charlie

Theory	Evidence	Notes
Charlie's eidetic memory could be a result of the blood clot in her brain. As Chandra Suresh began his research thinking that defects in the brain could be corrected, they could possibly also cause a power to emerge.	Chandra's comments about Shanti Suresh
Charlie is merely a victim of time. No matter how much Hiro bends time and space, Charlie dies at the same time.	Hiro tells Ando he couldn't save her, no matter how hard he tried
Hiro actually did save Charlie from being killed by Sylar, but she still died in the present because of her blood clot.	None	Mr. Bennet shows Eden the photo of Charlie dead.(Episode:Homecoming) Ando still remembers her murder, and tells Isaac about it.(Episode:Fallout)
Charlie's blood clot in her brain was only the beginning stage of her power, and she is still alive somewhere.	None	Mr. Bennet shows Eden the photo of Charlie dead.(Episode:Homecoming) Ando still remembers her murder, and tells Isaac about it.(Episode:Fallout)
The Haitian visited Charlie and erased some of her memories.	In Seven Minutes to Midnight, she says that she had started only a week before reading the Japanese phrase book she received for her birthday six months earlier. In Six Months Ago, she started using the book right away. Altering her memory may have interfered with Hiro's efforts to save her — even though he bought her a ticket to Japan, her memory of being told to leave was erased.
Charlie knew of her impending death, and of Hiro in the changed time line. She simply did not acknowledge that she already knew Hiro. She accepted her death at the hands if Sylar because she was going to die of the blood clot anyway.	Ando doesn't remember anything differently.	This doesn't account for the changing photo, however.
Hiro's actions did create some changes in the past, but he is apparently unable to make a change that would create a causality paradox: he cannot change the past in such a way that it would prevent him from going into the past.	The different versions of Charlie's birthday photo (and Ando's reaction to the change) indicate the past has changed

Mr. Bennet

Theory	Evidence	Notes
Mr. Bennet is the cooler. He doesn't repel powers. Heroes powers do not exist around him.	None	Nathan was able to fly. The writers have confirmed in an interview that blocking powers is part of the Haitian's abilities. Jack Coleman also stated in an interview that at this point Mr. Bennet doesn't have any special powers.

Mr. Bennet's boss

Theory	Evidence	Notes
Mr. Bennet's boss is Mr. Linderman.	Linderman is connected to most of the heroes in some way.

The Deveaux Society

Theory	Evidence	Notes
Some fans have speculated that Mr. Bennet, The Haitian, and Eden McCain are part of this society.	None
Some have thought that the Society might be a group founded by Simone that acts as connection between the evolved humans and the rest of the world, or as a therapy group to help them deal with their powers.	None

Explosion

Theory	Evidence	Notes
Ted Sprague is the cause of the explosion	He intimates that if he were to die, he could explode like an atomic bomb. (Episode:Nothing to Hide)	In Peter's vision, he's the cause of the explosion. However, the veracity of the vision is not established.
The explosion could be a "rift" of the kind which Future Hiro warned Peter about. This could have been caused by Hiro taking the comic book back in the past with him, and that is what it looks like when things are taken out of their proper place in Space/Time.	None	Peter believes he is the cause of the explosion, but could be incorrect.
Peter Petrelli is the cause of the explosion	Peter's vision (Fallout)	Peter's dreams don't seem to always be prophetic. His shared dream with Charles Deveaux didn't come true, for example
Peter absorbs Ted's abilities and becomes the bomb.	Consistent with Peter's vision, Peter's powers, and Ted's statement
Peter absorbs all of Heroes' powers, which cause him to overload and blown up the city.		Peter has yet to manifest more than one power at the same time, but it's possible that he can.
It's the simultaneous combination of Ted's abilities and Claire's that allow Peter to reach some sort of 'critical mass' without dying so as to be able to explode.
If you look at the watch on Peter's wrist right when he comes into the explosion dream, you get the possible time it happens. Although it isn't completely clear it looks to be about 7:05, which would fit in with the lighting. Also the watch looks similar to the one Gabriel was fixing in Six Months Ago when he took the name Sylar. Peter's trenchcoat is also similar to Sylar's
The city is evacuated, the other heroes are running away, and Claire mouths "I'm sorry". Also, his brother, Nathan, comes outside and stands beside him. This could be so that when Peter explodes, he can fly upwards and reduce damage.	This explains why in the preview for the next episode, there are seemingly fire trucks spraying water on buildings. This view is the same that Hiro had in the future, except in the future, the buildings past that (including the one he was standing in) were also destroyed.
If Peter turns out to be the cause of the nuclear blast, one possible escape would be for him to mimic Hiro's powers and jump back in time to the Mesozoic Era (a time in which a nuclear blast may be considered to have much less impact on the state of the world today -- humans have not yet evolved and many forms of life will eventually become extinct).	No direct evidence so much as speculation for motivations for apparent future events.	This could possibly be where Peter gets his scar.
Hiro jumps back to prehistoric times in order to find Peter and lend him the ability to return to the present day.	If the above turns out to be the case -- Peter saving NYC from the nuclear blast by taking it with him into the prehistoric past -- the others may realize or fear that Peter would be unable to return without being able to tap Hiro's powers. This could be a possible motivation for Hiro traveling back to a time and having to face a t-rex. In Isaac's painting of Hiro facing a T-rex, Hiro is still wearing his glasses implying that the dinosaur confrontation will occur prior to becoming the future Hiro who met Peter on the train. The painting also depicts Hiro wears the same general outfit as currently worn in Fallout and in Peter's dream of exploding, suggesting his trip may happen fairly soon. This would be consistent with the explanation of traveling back to save Peter, though far from conclusive as Peter is wearing entirely different clothes in his vision of exploding (after all, changing clothes isn't that difficult a task).	Much of this is, of course, a speculative explanation for various events.

Exterminator

Theory	Evidence	Notes
The exterminator works for Mr. Bennet, and his appearance was a ruse for Mohinder to meet, and trust, Eden.	Eden was planted by Mr. Bennet, and the gun the exterminator uses is the same style as the weapon Eden attempted to use on Sylar.

Hiro's sword

Theory	Evidence	Notes
Future Hiro has come from an apocalyptic future where one needs a sword to defend oneself.	None	Based on Isaac's painting, it appears he'll get the sword long before any apocalypse
Since a gun would be completely useless if time were frozen, he uses the sword to defeat enemies.	Hiro can move objects when time is stopped, but there's no evidence he can allow objects (like bullets) to move of their own accord.
He uses the sword to channel his powers.	None
Some heroes, such as those with Claire's regeneration ability, might have to be decapitated to be killed, as in the "Highlander" mythos, particularly Sylar	None
He thinks having a sword would be cool.	His reaction on learning the message	While true, he first becomes interested in actually getting the sword after seeing Isaac's painting
Nightcrawler (a Marvel Comics character who possesses teleporting superpowers) uses a sword, and Hiro is a member of the Marvel Merry Marching Society.	None	As or more likely a coincidence than a rationale on Hiro's part.
With the sword, he will be a deadly adversary, since he will be able to stop time, attack his adversaries while they are helpless, then allow time to resume so that they will feel the effects of the wounds. It is hard to imagine how anyone will be able to defeat Hiro if he has enough warning to use his power to control time.	We've seen that when Hiro "stops time", he can still interact with people and objects that are "frozen".	This may be significant regarding Sylar's apparent resistance to bullets. The sword may be instrumental in defeating Sylar if/when the explanation behind his "bulletproofness" is further explained.
The sword will come in useful on Hiro's predicted trip back in time where he must confront a dinosaur.	Hiro expresses grave concern over making significant alterations to history such as with stepping on a bug. He may consider this reasoning as well for using a sword (aside from fulfilling Isaac's painting vision and Peter's report of meeting future Hiro carrying a sword.	Part of the motivation could be Hiro needing weapons as defense and not wanting to bring back firearms which could leave bullets or casings in the fossil record potentially altering discoveries in paleontology. (This presumes he succeeds in eventually leaving that time and doesn't become part of the fossil record himself, along with his sword.)

Isaac's paintings

Theory	Evidence	Notes
Isaac finally paints one that shows that Sylar will be on the hilltop after the incident at the high school. Eden goes there with The Haitian, and together they apprehend him. This would explain how Eden and The Haitian were casually waiting (and hiding), knowing Sylar would appear.	Mr. Bennet asked Eden to make Isaac another painting	Eden refused to force Isaac to use heroin again. Mr. Bennet told Eden to use the paintings as a guide, so they were up there because of the former paintings not any new ones.
The visions in Isaac's paintings may be inevitable and fated to occur.	So far, the envisioned imagery occurs, even if the underlying event/circumstances are not as initally expected, i.e. a cheerleader died even though it did not turn out to be Claire as believed and feared by the characters. This would be in contrast to Hiro witnessing evidence of Isaac's death in a possible future that may or may not be preventable or altering time such as by inserting himself in Charlie's birthday photo where originally he was not. By this reasoning, the explosion, or the vision of it at the least, may be fated to occur simply because Isaac has already painted it (presuming it is one of his vision paintings, as it seems to be).	In an interview, the writers implied that Isaac's paintings are only a possible future outcome. Nevertheless, so far they have all come true.

Iyer, Sanjog

Theory	Evidence	Notes
Sanjog is Sylar	Sanjog's first initial and last name is "S.Iyer".	Sylar is Gabriel Gray
Sanjog is the ghost of Mohinder's sister Shanti	None	Sanjog is a living boy. Shanti is a dead girl. (Homecoming)
Sanjog is stuck in the dream world.	None	Mohinder meets a very much awake Sanjog. (Homecoming)
Iyer may have the power to see the past, not just entering other's minds while they dream.	He was able to see the murder of Mohinder's father, for example.
Sanjog was murdered by Sylar, and Sylar obtained his ability. This is how Sylar appeared in Peter's dream when he was in his cell in Fallout.	Nathan changed from Nathan to Sylar in Peter's dream in Fallout	Sanjog was most definitely still alive during the events leading up to Homecoming, because Mohinder met him. It's possible that Sylar killed Charlie in Midland, flew to India, killed Sanjog, and flew back to Odessa, but it seems unlikely.

Mr. Linderman

Theory	Evidence	Notes
Linderman is Sylar.	None	Sylar is Gabriel Gray
Linderman will eventually play a bigger part in the series.	He is already connected to most of the heroes
Linderman may be Mr. Bennett.	Mr. Bennet is able to access Nathan's room in Linderman's hotel.	Nathan Petrelli knows Linderman, but he didn't recognize Mr. Bennett when he was kidnapped by him.
Linderman may be funding the AWI.	He has money, and is connected to most of the heroes.
Linderman could be Hal Sanders.	He's never seen, he has quite a bit of money, and he lives in Vegas.	He would have had to have sent men to collect from his own daughter, and have blackmailed her into sleeping with a married stranger. Hal, while an abusive, murdering alcoholic, doesn't seem that depraved (yet).
Linderman is Mr. Bennet's mysterious employer.		See "Linderman is funding the AWI"

The list

Theory	Evidence	Notes
Sylar is using a copy of the list to locate his victims.	According to Mohinder, six of the people on the list, including James Walker and Charlie Andrews, have been killed
Sylar killed Chandra Suresh to obtain a complete copy of the list.
Some fans also believe Mr. Bennet is using a copy of the list.	He has located some of the evolved humans on the list, notably Nathan Petrelli and Matt Parkman	However, his organization predates Chandra's research, so if he is using it, it's a recent development. Perhaps previous to Suresh's list the AWOI was merely stumbling across the special people. With the list they could target them far from home where time off wouldn't be missed. The preview after Episode:Fallout makes it clear that he's at least aware of the list.

The Mark

Theory	Evidence	Notes
The mark may be used by Mr. Bennet and The Haitian to mark heroes they've already encountered	Both Matt and Ted were abducted. Both have the mark.	To date, the Haitian has used his powers on Ted, Matt, Sylar, Eden, Zach, Sandra Bennet, Lyle, and possibly Claire. He attempted to use his powers on Nathan.
The mark may be an immature state of Jessica's marking of the symbol, indicating that the mark might develop as the character gains more experience with their powers.	The double lines look similar to those on The Symbol	It seems likely that Ted's powers have been around awhile, and Matt's powers first appeared roughly the same time as Niki's. If the mark was an indication of how long the hero had been using their powers, their marks should be more like hers. Also its been indicated that the mark is meant to resemble an RNA symbol, see below.
The mark may be used merely to denote a connection between the two characters, possibly in opposition to characters marked with The Symbol like Jessica and The Haitian.
The mark is a scar left by an insertion of a tracking device.	Greg Grunberg implied this in an interview with TV Guide
The mark is a side-effect of the Haitians memory-erasing ability.		It hasn't been shown on others he has mind wiped, but that doesn't necessarily mean it isn't there.
The Symbol is a representation of RNA, so the mark is something else.	Symbol directly resembles RNA, but missing a rung....which might be the actual genetic abnormality.	Sylar was noted to be messing with his DNA and probably RNA as well...RNA is also in the brain, which would make sense to this theory.

The Message

Theory	Evidence	Notes
Claire's life will somehow be put into danger in a non-physical sense.	Her ability to regenerate makes her immune to most physical threats	Sylar removing her brain seems like a physical threat. As seen when she "died"" during Brody's assault, an injury to the brain can prevent her from healing. However, since Future Hiro didn't specify what she needed to be saved from, it's possible she's still in danger.
Claire may be in danger of being killed by having her brain removed by Sylar.	This is supported by one of Isaac's paintings.	Isaac's painting depicts Jackie, but Sylar only attacked her because he thought she was the evolved human. As he tells Mr. Bennet in Fallout, he would have done the same to Claire.
Claire's survival is critical, so that Peter will be able to utilize her regenerative ability in a showdown with Sylar.
If Sylar is able to remove Claire's brain, he will become indestructible and destroy the world.
The message is two different commands, meaning the heroes have to save the cheerleader, and save the world.	Ando seems to think so.	Hiro thinks the latter part depends on the former part, and it's his "future self" who gave the message.
Claire's regenerative ability will be used to enter the radioactive area caused by the explosion to stop Peter Petrelli (or possibly Theodore Sprague) from dying/overreacting.
The message is vague for a reason. Had Future Hiro been too specific with the message (relaying Claire's full name, her address, or even the town where she lived), he might have eliminated his reason for traveling back to the past to begin with (causing a rift). Had this occurred, he would instantly have been pulled back into his "present"	This is similar to what happened after his attempt to persuade Charlie to come to Japan with him.

Parkman, Matt

Theory	Evidence	Notes
Matt is in a different time than the rest of the heroes	Prior to Fallout, the only events connecting Matt to the rest took place Six Months Ago.	He interviews Peter and Claire in Fallout. Audrey mentions he still hasn't called his wife since finding out about her affair.

Peter's visions

Theory	Evidence	Notes
Peter's visions are not entirely predictive and can be changed.	When Peter explodes in his vision he does not yet have a visible scar which future Hiro said he will have. Also, his dream about Charles Deveaux didn't come true	It's possible that Peter received the scar in the timeline in which Claire was not saved, and will not now receive the scar, although that would mean Future Hiro created a causality paradox.

Petrelli, Monty & Petrelli, Simon

Theory	Evidence	Notes
It is possible that Monty and Simon might have powers inherited from Nathan.	Micah is a second-generation evolved human, as is Claire. Nathan and Peter are evolved siblings.

Petrelli, Peter

Theory	Evidence	Notes
Peter's power may be empathy. This would give him the ability to channel powers and would explain his prophetic dreams about Nathan, and explain how he knows what he felt.		This would also match the theory that their abilities are based on their personalities...or personality on abilities. Peter became a nurse to help people, so gaining empathy would just further his wanting to help.
Peter's power is a sort of "resonance" with other minds. Since powers supposedly result from a particular mutation of the brain (Six Months Ago), this would explain how he mimics the powers of others. It could also explain his "empathic" visions.
Peter has some unknown additional power that is or causes these dreams and blackouts.
Peter's impending explosion, foreseen in Fallout, may be caused by the proximity of many other evolved humans, whose power he absorbs all at once; it's too much power for him to handle.	After being in close proximity to several others in a short time, Peter appears weak and sickly. (Fallout)
Peter's vision of himself exploding may not be a prophecy; it may be form of empathic communication, like some of his other dream experiences seem to be.	His dream about Charles Deveaux was not prophetic	If so, Peter is wrong to think he will be the cause of the explosion.
Peter may use the vision as a warning that he needs to learn how to better control his powers in order to prevent a disaster like the explosion. He may now start making an effort to learn to control his powers in order to prevent the explosion from happening or to limit it's destruction.	Spoilers indicate he will gain a mentor who helps him control his powers
As seen in a painting in the background of Isaac's room at Primatech Paper Co, Peter could evolve into something akin to the Human Torch.	Isaac's painting
If Peter's power is mimicing/copying the special abilities of others, why did he stick just to Claire's healing power when he was very close to Sylar (and a bit farther away from Eden and the Haitian)?		We don't know how close Peter has to be to another superhuman to duplicate their powers, or how long he has to be near them. Also, he may be unable to duplicate the acquired powers of Sylar (as opposed to his innate power of intuitive analysis). Also note that Sylar used his acquired ability of telekinesis to launch lockers that did not hit Peter. It is possible that Peter unknowingly used telekinesis to prevent damage to himself. This was suggested in the Q & A session with the witers. It also looks like the lockers are just flying around him. It is probable that Peter had access to all of Sylar's powers, but did not know how to wield them.
In the vision, Peter explodes from mimicking too many powers at once		From the way the other heroes are responding to him, this seems most likely. Claire says she is sorry, Simone is running to him, Nathan is walking towards him determinedly, etc...
In the vision, Peter sees himself as Theodore Sprague who is the one that loses control of his powers and goes nuclear.
In the vision, Peter sees himself as Sylar, who loses control of Theodore Sprague's power after stealing it.	His trenchcoat and watch are similar to Sylar's
Peter is manifesting the abilities of a female human torch whom we have not yet met	"A new female hero is joining the cast for a mini arc, and this person's power is unlike anything we've seen on the show so far. All I'll say is, she'd come in very handy on Survivor." Source: Ask Ausiello @ TV Guide)	In Peter's vision, the others act afraid of him, even before anything happens. If they knew he was going to "explode", they would be running away a much faster.
Peter exploding may be a self-fufilling prophecy	Some of Isaac's paintings have happened because the paintings were seen	Peter will contact the others and tell them he is the one who is going to explode. Theyll believe this because of the exploding man painting and barracade the city, etc. Then since he will be by all of them at once he will explode becuase of it. And he would not have if he hadnt contacted them all.
Peter's Regeneration after his encounter with Sylar was incomplete.	When we see Peter in Fallout, he is coughing and sickly. It would appear that he did not heal completely.	Peter's illness could also be attributed to overuse of his powers or coming into contact with too many other heroes in too short a timespan.

Rift

Theory	Evidence	Notes
Hiro may have experienced a rift in Six Months Ago, when he tried to go back in time to prevent Charlie's murder.	In the episode, they had just confessed their love for each other and were about to kiss when Hiro abruptly and unexpectedly jumped through time to the present. He later told Ando that he tried repeatedly to go back to save Charlie, but couldn't.	In theory, space-time spontaneously corrected itself to keep Hiro from creating a causality paradox; he could not do anything in the past that would keep him from having a reason to go to the past.

Sander, Micah

Theory	Evidence	Notes
Micah will build a suit similar to Iron Man's.	None	There's no evidence that Micah's abilities extend to building new technology. He's only been shown repairing existing technology.
The most likely power that Micah was exhibiting is known as technopathy, or the ability to control technology with one's mind.	His repair of the payphone fits with other depictions of this power.	However, all we've seen so far is the temporary repair of existing devices (motherboard, telephone).
Micah will build a cybernetic limb, like Forge and Cable; a time machine like Forge and Cable; an evolved human tracking or detecting device.	None	There's no evidence that Micah's abilities extend to building new technology. He's only been shown repairing existing technology.
Micah will become a first-class computer hacker.	None	His abilities shown to date are all hardware, not software, related.

Sanders, Niki

Theory	Evidence	Notes
Niki has multiple personality disorder and Jessica is her alternate personality. For some reason, only Jessica is able to tap into her powers for now.		If she in fact has MPD, or any sort of disorder, it would appear she also has some form of schizophrenia as well, due to her ability to speak to and see Jessica.
Niki had control of her powers at one point, but HRG captured her, and had The Haitian wipe her memory. Her old personality, that The Haitian erased might not have been fully erased, which explains her alter-ego.		However, this does not explain all of her friends/family knowing her as Niki and not as Jessica.
Niki will go to the "dark side".	None
Niki's other personality is actually her sister Jessica, who may have had an ability before dying and somehow came to take over Nikki's body so she could continue protecting her.	The Jessica persona definitely believes it's the dead sister. In "Six Months Ago", the way Jessica (Personality) speaks is as if she is Jessica.
Niki is a medium. She can talk to the dead but has so far only had contact with her sister Jessica who takes over Niki's body when she has things to take care of.
Given that Niki is a close analogue to Marvel Comics' Incredible Hulk, if this homage continues, we may see an even stronger rage based personality or a full integration of the two (via hypnosis?) in the future.	Both characters were abused as children, have physical and personality changes brought on by stress, and powers only accessible to one personality state
Niki can theoretically tap into the same power, but doesn't know how.	The source of Jessica's superhuman strength is somehow a part of her brain, as are the abilities of other evolved humans, and the personas share a brain

Sprague, Theodore

Theory	Evidence	Notes
Theodore is the source of the explosion in New York.	Ted says he doesn't know what would happen if he were shot, that "Maybe I'll wipe out this whole city like an atomic bomb!"
Theodore is the bomb. Peter absorbs his power to contain radiation. Peter then becomes the bomb.	As above

Sylar

Theory	Evidence	Notes
Sylar is Mr. Linderman or works for him.	None	Sylar is Gabriel Gray. He seems to be working alone.
Similarly to Peter, Sylar has the ability of absorption. However, Sylar has found a way to prolong the effects indefinitely, through Chandra Suresh's research. He knows that if he eats the brain of someone with abilities, he is able to control those abilities.	This is the reason why the heroes must Save the Cheerleader. If they don't save Claire, then he will gain Rapid Regeneration and will become almost unstoppable.	Sylar is absorbing powers, but he is not a power mimic. He was able to discover how to absorb powers without Chandra's help.
Sylar was a test subject of Chandra Suresh who manipulated his genes to give him all of the researched powers. This manipulation, however, has had a terrible side effect which causes his split personality (like Niki) to be extremely violent.	Sylar's message	Sylar discovered how to absorb powers without Chandra's help, and his insanity, while probably exacerbated by his new powers (according to Mr. Bennet in Fallout), predates it.
Sylar might have every power the heroes have combined.	Sylar seems to exhibit multiple powers	While Sylar is confirmed to have multiple powers, he'll only have the powers of all the heroes combined if he kills them like his other victims.
Sylar is Peter	None, apart from similar powers	Sylar is confirmed to be Gabriel Gray
Chandra Suresh moved to the United States to further his research; He joined forces with Mr. Bennet to perform this research, which involved the testing of Sylar. Chandra and Mr. Bennet became divided over ethical approaches, and Sylar, without help or containment found that he could gain others' abilities if he ate their brains.	None	Mr. Bennet and Chandra Suresh were not working together before Sylar began killing. (Six Months Ago) Sylar did develop the ability to absorb powers independently, but there is still no evidence that he eats brains.
It's possible that Sylar is not absorbing the heroes' powers, but is only a powerful telekinetic.	All powers exhibited initially could be explained as telekinesis	Sylar's telekinesis is itself absorbed. (Six Months Ago) Mr. Bennet confirms that Sylar has multiple abilities. (Fallout)
Sylar is dying because he attained his powers unnaturally or because his mutation ("power") was fatal, and the only way he's staying alive is by consuming the brains of other evolved humans.	None	While it's possible that either Sylar's power or his acquired powers are damaging him in some way, there's no evidence to support such a conclusion. Additionally, it's confirmed that he is taking (but not necessarily eating) brains to absorb powers.
Sylar's powers have something to do with emotion, due to what Chandra says to him and his intonation in Six Months Ago.	None	Sylar may have some sort of emotional power in addition to his others, but there's little evidence to support such a theory.
Sylar can alter his brain by studying the physical characteristics of other brains, which is why he is able to alter his own abilities.	Sylar's gift of fixing objects and the profound instance when Sylar noticed his first victim's 'defect' supports this theory. Sylar can fix intricate devices, and brains, specifically his own. Micah seems to have a similar gift.	Sylar's Intuitive Aptitude was confirmed in Fallout, but there's no clear evidence how he absorbs powers. Knowing how things work and being able to alter his own brain seem like two distinct powers. He has not yet fixed anything, mechanical or biological, other than manually. In Fallout, Mr. Bennet said it was his DNA he was altering.
Sylar takes the brains and somehow figures out how to take the parts with the ability and place it in his brain. He has convinced himself that either all the Heroes are broken or incapable of their abilities, or that he needs the powers just to satisfy his hunger for power.	Sylar's Intuitive aptitude	His comments to Mr. Bennet in Fallout support the idea that he is acquiring powers to be more "special".
Sylar believes all the Heroes need to be "fixed".	Sylar's Intuitive aptitude Episode 13 is titled The Fix	To get "a fix" is also a term used by drug users, meaning to satiate their need for their drug of choice. This could be a reference to Isaac or perhaps Sylar's own need for power.
Sylar may be heeding to the Evolutionary Imperative to kill dying Heroes and augment their powers to his for the sake of efficiency.	This would explain Charlie, who is dying from a blood clot, and possibly Brian Davis.	However, Evolutionary Imperative doesn't state anything about greed, so he might kill people out of his lust for being "special"
Sylar may also be a thematic foil to evolution itself.	His profession of watchmaker is often used as an analogue to an intelligent designer. Rather than following an Evoltionary Imperative, he appears to be redesigning himself using existing powers as a template which he then improves upon.
Sylar is meant to be Peter's literary/thematic antithesis.	He has a similar motivation (to be special), similar looks, (perhaps) similar powers, and both men have even talked to a Suresh who ultimately gave up on him before he could prove that he was special
Sylar is suspected to have learned one or more of the following powers from his victims: cryokinesis, regeneration, super-jump, or flight:	Molly's father is frozen solid while eating dinner, mid bite, with the top of his skull removed. (Don't Look Back) After being hit by several of Matt's bullets, Sylar rises a minute later, almost "lifting" himself from the floor, seemingly unharmed. The sound of metal hitting to the floor is heard, as if Sylar was able to shield himself from the bullets. (One Giant Leap) Sylar escapes, possibly by leaping up the wall or flying. (One Giant Leap) Sylar is relatively unharmed after a fall which badly mangled Peter. (Homecoming)	Syler could have used his telekinesis to stop the bullets, lift himself up (giving the appearence of flight), and could have possibly protected himself from the fall with the same power.
Sylar may have unwittingly gained Charlie's blood clot when he killed her to acquire her power.	None	Given Sylar's ability to understand complex systems and repair them, he would probably have detected the clot and not duplicated it in himself.

Sylar's victims

Theory	Evidence	Notes
Sylar also possesses the power of cryokinesis	James Walker was frozen. (Don't Look Back)	Mr. Bennet confirms Sylar has more than one power. (Fallout) However, he hasn't shown any sign of using it since James's murder.
Sylar is stealing the brains of evolved humans in order to incorporate their abilities into himself.	Most victims whose brains have been removed have been evolved humans	Sylar has corroborated this theory with his own statements. (Fallout)
Sylar may need to physically see the functioning brain (or believe he does) in order to give himself that power.	He is removing and taking brains, not merely observing their owners.

The Symbol

Theory	Evidence	Notes
Is meant to resemble RNA, which is where the abnormality lies...or just to indicate something to do with the abnormalties	Symbol directly resembles RNA, but missing a rung....which might be the actual genetic abnormality.	Sylar was noted to be messing with his DNA and probably RNA as well...RNA is also in the brain, which would make sense to this theory.

The train wreck

Theory	Evidence	Notes
The missing painting in Isaac's wall-sized comic may be one of his paintings of the derailment or Claire inside the train car	This could potentially lead the Heroes to Odessa.	The missing painting was revealed in Homecoming
The train may have been derailed in order to steal nuclear material	According to the newscast Isaac sees, it was registered to the Nuclear Regulatory Commission.	See In His Own Image

Uluru

Theory	Evidence	Notes
He is actually a depiction of Sylar or a symbol thereof.	His being invincible would have to do with the rapid regeneration ability he was planning on taking from Claire. It could also depict how his hunger for power will spiral to massive proportions

Walker, James

Theory	Evidence	Notes
James Walker possessed the power of cryokinesis. Sylar killed him and removed his brain to obtain his power, then tested the power on his body	James Walker's body was found frozen, with his brain removed.
James Walker was killed using cryokinesis before his brain was taken.	James was frozen in mid-bite while eating breakfast; he would not be in this position if he wasn't frozen before his brain was taken.

Walker, Molly

Theory	Evidence	Notes
Molly is Claire at a younger age (assuming the Matt storyline is in the past).	None	Matt's timeline was conclusively established in Fallout
Sylar believes Molly is an evolved human	It's not yet clear what Sylar's interest in Molly or her parents is, or whether any of them are evolved humans. However, since the only other of Sylar's victims shown with their brains removed have been evolved humans (Isaac Mendez in the future, Charlie) or believed by Sylar to be an evolved human (i.e., Sylar thought Jackie Wilcox was Claire Bennet), it's quite likely that at least her father, who was on the list, possessed superpowers.
Molly might have the ability to amplify powers, thus making her a highly desirable target for Sylar.	This would explain Matt's ability to hear thoughts from well outside the house, at a time when his powers were new and unfocused.

Zach

Theory	Evidence	Notes
Zach is Sylar.	None	Sylar is confirmed to be Gabriel Gray
Zach has an unknown ability.	None
He is killed because of Claire.	None
He is gay.	His comments in Homecoming, among others. His MySpace profile.	Confirmed offscreen by Tim Kring in an interview with Out magazine.
He has deeper feelings for Claire.	None, except that he seemed to care for her a great deal before his mind wipe
Zach will be the one who eventually saves Claire, possibly with his theoretical ability.	None	Claire has already been saved once, by Peter Petrelli in Homecoming
Zach is actually Claire's twin brother. He knows it, but she doesn't.	He won't date her and yet tries to be very close to her.
He will be curious as to why Claire was acting the way she was and will eventually rediscover her power.	None