Who will die in heroes season 4 2009?

In "Heroes" Season 4, several characters face significant danger, but one of the most notable deaths is that of Nathan Petrelli, who is killed by Sylar in the episode "Upon This Rock." Additionally, the character of Gretchen is also killed by the antagonist, Samuel Sullivan, during the season. The season features high-stakes drama and confrontations that ultimately lead to these pivotal deaths.