He is playable if you add him to the household via cheats or delete this trait. The wolftown_greg trait is controlling his behavior in game, being aggressive and forgetting people who spoke to him before. It also gives him constant fury. If you delete it, he is just like any other apex werewolf. You can also play with him with this trait, but others will still need to go through “attempt to communicate” debacle after some time. He will be able to act normally, but will queue brawl on his own from time to time. Also game will not spawn another Greg, even if you delete the trait and play with him.
