Kring speaks about Heroes Volume 3

Caution - Very slight spoiler alert

Via TV Guide - Exclusive: Tim Kring Explains Heroes' "Generations" Finale

The fate of Nathan, who was shot during a TV press conference, and of Niki, who may have died in an abandoned building explosion, are "up in the air and will be determined when we come back after the strike," Kring says.

[. . .]

Not to worry. There are plenty more baddies coming after the writers' strike concludes. In fact, the title of Volume 3 — "Villains" — says it all.

"We've introduced a cadre of them over the course of the show and we're going to see them rise up," Kring says. "Just as the heroes have found each other to save the world, the villains will do the same with the opposite intent." And their numbers may be legion. "The Company has catalogued many of these people over the years. There may be more of them down in that basement than we have alluded to so far."

And there is an upside to the writers' strike:

Originally, Quinto was not going to be available for much of Volume 3 because of his commitment to the new Star Trek film. Now, with the strike dragging on, he'll likely be done playing young Spock by the time Heroes returns to production.