Theories

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

Sylar

~~Sylar is Mr. Linderman or works for him.~~
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 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 might have every power the heroes have combined.
The theory that Sylar is Peter has become so stale at 9th Wonders, the semi-official Heroes fansite, that it has inspired a drinking game: whenever someone brings it up, drink.
Chandra Suresh moved to the United States to further his research; He hooked up 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.

Claire's life will somehow be put into danger in a non-physical sense, seeing as how her body regenerates.
Claire may be in danger of being killed by having her brain removed by Sylar. This is supported by one of Isaac's paintings.
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 (and possibly consume) Claire's brain, he will become indestructible and destroy the world.
The message is two different commands, meaning the heroes have to save the cheeleader, and save the world.