War Aeternus: The Beginning

Lee is a quiet and unassuming office worker who leads a life of solitude, comfort, and routine. Day in and day out, he shuts off his brain, keeps his head down, and goes about doing his job and minding his own business. That is, he does until a drunken god shows up randomly one day and whisks him off into another world, demanding that Lee serve as his pawn in a game between the gods. Now, trapped in a completely different world full of danger, magic, and creatures he's never imagined outside of fairy tales and video games, Lee has to figure out how to stay alive long enough to make it back home.

Warning: This book has deities and a conversion mechanic.