I'm giving this manga a review because someone needs to balance things around here. This manga is not what you'd call good. It is, though, hilarious. Also, it's quite metal, in a way.

Manga is entertainment and there are many ways to be entertained. In this case, you'll enjoy the story if you like to laugh out loud at bad dialogue, stupid character decisions and general youthfulness in immortal characters. The completely cliche plot and trope characters make the dialogues and situations so much fun you won't drop it until you finish reading.
Then you'll go and write a review like this one.

As for art, the less is said the better (though the boys are cute).

Overall: you might have fun (as I did), but it'll probably just be a waste of precious time. Unless you're very into BDSM.

PS: If you do read it, I dare you not to shout "SATAN!" whenever the main character does. It's compelling.