The story has a Chrsitian theme, but this is a very light veil, don't go in expecting anything related to religion. It has MC, Ritsu, possess the Ring of Solomon, which allows the welder to summon the 72 demons. However, Ritsu just wants to free demons from the ring's contract, and the story focuses around trying to free the only demon whose contract can't be unsealed, Asmodeus. The story was cute until chapter 25 when Leo kills Ritsu in cold blood but eventually turns out good, ingoring the obvious problem of murder the plot itself felt forced, could Leo not have just asked Ritsu to free the spell first using his demon aide to spy on Ritsu? The game arc in volume 5 or 6 was an enormous waste of time, without any plot devlopment. It felt like fantasy or isekai at that point, which I explicitly avoid when reading manga. Given this manga ended 10 chapters later, I'll assume the game plot killed the manga. A shame too, as the story, once back to its worldly environment, was getting exciting again. I'm surprised this was published as seinen, as I've seen much Shounen manga more mature than this. Although, the ecchi was damn exciting. Come on, demon harem? I can't resist and this likely saves the manga for me.
6/10.