Tsuzuki is one of the shinigami detectives who are the two main characters--the other is his partner, Hisoka--in the shoujo/shonen-ai-ish series Yami no Matsuei / Descendants of Darkness. There's an 11-volume manga by Yoko Matsushita (that's unfinished and stalled since the mangaka went on hiatus in 2003, but she's supposed to be picking it up again sometime this year), and a 13-episode anime adaptation that overall I like I much better than the manga.