One of the autumn's titles that didn't get much attention, perhaps because of the unusual animation style, with a lot of rotoscoping for backgrounds, and an almost European feel to the character design, except in occasional bursts of nigh standard anime look in the intro vignettes to most episodes.
The basic premise is that there are man-eating monsters who usually live concealed in human form; and there is a clandestine society of hunters who act to keep society at large free from predation. The heir to the society falls for a girl — but you guessed it, she's a Flesh Eater. Cue, one would think, Romeo and Juliet with martial arts mayhem. But no.
If there is anything that this builds on, it is Nietzsche's line about being wary of fighting monsters, lest one becomes one as well. Factions splinter, divisions blur, and things start falling apart as the intermittently happy couple try to stay ahead of pursuit. And by falling apart, I mean descending into serious madness, of one of the most messed up and depraved villains gets close to succeeding in dragging the whole world down with him.
Definitely 18-rating stuff, but definitely one of the more original titles of 2006. It's not every day your hero fights to freedom while bound naked (but for handy censoring blur) to a chair.