After months of speculation, during which the likes of Jon Hamm and Garret Dillahunt were linked to the role, AMC has finally confirmed who will be playing Negan in The Walking Dead - Jeffrey Dean Morgan. Seeing as Negan is a savage leader of a group called The Saviors this will be quite a departure for Morgan. Up until this point, he's largely stuck to nice guy roles with turns in Supernatural, The Good Wife and Grey's Anatomy.
On the other hand Negan is a brutally violent sociopath with a sailor's mouth who thinks nothing of wiping people out to prove a point. Usually using the baseball bat he carries around, wrapped in barbed wire no less, that he lovingly calls Lucille. All those comments about him making The Governor look like the Easter bunny? They're not wrong.
Negan first appears in issue 100 of the comic when Rick stumbles across him during a supply run. The vicious group he leads roam communities and extort supplies in order to protect them, including Alexandria and the as-yet-unseen Hilltop community with whom Rick and co team up to fight back. He's expected to make his first onscreen appearance in the season six finale.