Piers Anthony’s Incarnations of Immortality series of books. The first book alone, where a guy who was about to unalive himself accidentally kills death instead as he walks in the door to take his soul, would make an awesome series. Each book takes on a different aspect of Immortality (Death, War, Time, Nature, etc.) and how they overcome Satan by not being used for ultimate evil.
That last sentence may seem religion-forward but the author, Piers Anthony, is not a religious writer by any means. Another series of his, Bio of a Space Tyrant, could be an ultra gritty R rated Sci-fi epic with the right director.
I need to look into this, I was heavily invested in the Adept and Xanth series, and finding book 2 of Bio of a Space Tyrant, physically, is near impossible. I had no idea he was wrapped in any kind of controversy, but to be fair I haven’t kept up with him in over a decade.