One thing Eugene is great at is adapting to his surroundings. Since he appeared in season 4 he has shown that he will do whatever it takes to stay alive. Eugene isn’t the bravest character and he’s not usually the first one to step up when there is a tough job to be done. But in the past he has found his courage and stepped up to fight, like when Alexandria was overrun by walkers during the Wolves’ attack.
But in season 7 he betrayed his friends in Alexandria by joining The Saviors after Negan took him back to The Sanctuary. And he seems to be enjoying the benefits of being a Savior, including having Negan’s respect and getting to order people around.
Will Eugene really stay with The Saviors? Is he 100% Team Negan? He seems to be, but with Eugene appearances can be deceptive. He did make the poison pill that Negan’s wives wanted him to make. And he did help Sasha kill herself rather than become Negan’s pawn. So maybe there is still some hope for redemption for Eugene. Talking about Eugene’s future on The Walking Dead Josh McDemitt said:
"“My wish list for Eugene is that number one that he survives. Number two, that I would like to see him go further into the darkness. Right now he’s Negan, but I would like to actually see him be Negan, or be the guy controlling a community who feels like he’s completely justified in his actions but is the bad guy. That would be unexpected and that would be awesome. But ultimately, I just hope he survives.”"
Eugene has proven that he’s an expert at figuring out how to stay alive in The Walking Dead world, so Josh’s wish for Eugene’s survival just may come true.