Sad that Adam will not return, but I wanted to try a little interaction with Raguel and recently revived Adam as a sinner.
Adam believes that Raguel will be able bring him back to Heaven if convinced.

Note, There are some talks about Adam returning, maybe a flashback or something, but we can't be sure. The comic was mostly about Raguel's interaction with Adam, and I love the idea of Adam being revived as a Sinner. And Raguel is like a sheriff of Heaven whose job is sending angels who overstep their boundaries down to hell and keeping demons in check.

Adam @ Hazbin Hotel