Death of Alpha The Walking Dead Issue 156 pg 20

Negan and Alpha are two of the biggest villains in the Walking Dead.  Readers were not sure what Negan was up to when he left Alexandria and perhaps he did not either.  The Whisperers did not trust Negan to start but eventually gave Negan a knife to kill some zombies to make a skin suit to join them as a community.  After being upset that the Whisperers permitted sexual assault within their community, Negan was very upset and had a discussion with Alpha.  Eventually, to the suprise and shock of the readers, Negan kills Alpha with the knife they gave him.