bad to the bone
pretty thrilling angle they are playing here, with the whole who’s-good-who’s-evil thing/ying-yang-worldview. always a great device, and worked very well for harry potter. alas, it usually makes me very sad when a beloved hero turns to the dark side. eh, when in rome. there’s several good arguments to believe that any one of our protagonists could turn.
claire - two words: electra complex.
matt - also has daddy issues.
nikki - she’s just crazy as hell.
peter - power ALWAYS corrupts. see future barack obama.
hiro - he probably won’t actually become evil, rather perform some act of evil due to misunderstanding somebody’s english or vice versa.
nathan - someone shot him. he’s probably pissed about that.
mohinder - he realizes that he has no real powers. the audience then realizes it doesn’t matter if he’s good or evil due to his overwhelming insignificance.