There can be no redemption for Zach, but they'll try

From my point of view there is nothing that Zach can do or the writers can do to redeem him. I generally like a villain-redemption story, but there is no coming back from genocide. There is no way to forgive child-hitler.

I can accept a hero becoming a villain; I can accept someone being tricked into ending the world, I can even accept a childish villain like the warden in Deadman wonderland, but I cannot accept a petulant child committing genocide because his monster of a mom was killed.

He needs to suffer. He is worse than Joffrey. He's worse than Carl was at his lowest point on the walking dead. Spoiled children with mommy issues ending the world deserve a slow and painful death.