If you thought the Governor and Gareth were bad news, you ain’t seen nothing yet. That’s because the most notorious villain from The Walking Dead comic book is soon to be unleashed on the TV version of the show, which returns Feb. 14 on AMC.

At some point during the second half of season 6 we are going to be introduced to Negan, a barbed-wire-baseball-bat-carrying lunatic played by Jeffrey Dean Morgan who will show up to torment our survivors. He will be the latest — and greatest — obstacle for Rick Grimes and Co. And according to comic book creator and TV exec producer Robert Kirkman, his arrival will change things permanently, and not for the better.

“As far as shake-ups go, we have lots of shake-ups from season to season,” says Kirkman. “It keeps things interesting — keeps the blood pumping, I like to say — but Negan is kind of an atomic bomb that’s going to be dropped on the show and the show will probably never be the same after that. So buckle up, I guess?”

Negan is the leader of a group we met in the midseason finale’s prologue scene called the Saviors. We saw them stop Daryl, Sasha, and Abraham on the road while informing them “your property now belongs to Negan.” So who is this nefarious outfit and how do they differ from other groups we’ve encountered before?

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“I think the Saviors are dangerously organized,” says Kirkman. “The Wolves were psychotic, the Hunters [the group from Terminus] had a lot of weaknesses. When it comes to the Saviors, and Negan in particular, the way I’ve always thought about this in the comics is this is a group that’s led by a guy who’s had his morality dial a few clicks away from Rick toward the darker aspects of his personality, but is still an intellectual and capable leader who’s kept his group alive against all odds just as long as Rick has. It’s really the best encountering the best. When these two forces come head to head, things are gonna get interesting. This is a much different group than they’ve ever encountered. The Saviors are a group they’re not really prepared for.”