It does have undead. *nods*

Book fandom. Evil (with a capital E) undead sorcerer and a warrior priest unwillingly team up to track down memory stealing monsters. Then they save the world from a demon that feeds on sadism who is trying to alter humanity to bring that emotion to the forefront. (Oh god, so slashy. The priest actually goes to hell to pull the guy out in the last book. And they snark at each other the entire time.)

Panic! at the Disco. I think they're a band ;)