When Heroes returns to the air on September 21, viewers won't actually see Sylar.

But the iconic villain will be somewhere inside Nathan, who Parkman sort of resuscitated on the May finale, with the slight caveat that he's actually Sylar. (Following along so far?)

This act will have repercussions for Parkman, as well, though, as Greg Grunberg told TV Guide this week.

The detective is trying to be a normal family man, but there's essentially a devil on his shoulder, convincing him that he's meant for something else.

"The evil part of Sylar got stuck in my subconscious, and he is slowly gaining control over me," Grunberg said. "I have a feeling that he's going to make Matt do things that he would never, ever do in a million years."

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.