Manga by author Shiibashi Hiroshi

Rikuo Nura, a kid that is part human and a quarter youkai (demon), lives in a house full of spirits along with his youkai grandfather. Trying to escape his fate of acting like a demon, he does good deeds in order to avoid becoming one despite his grandfather's wish to succeed him as master of the Nura youkai clan. First published as a oneshot in 2007, it later became a series in 2008.

From MangaHelpers:Supernatural creatures live alongside humans, but these "rares" are being hunted to extinction over time. An organization is being formed to protect these rares, and allow them to live their lives as they like. The starting members of this organization are few; there's the masked Fukumen, the Black Vampyr king AxL, and they are soon joined by the sweet-voiced mermaid Mirror. Together, they will protect the rares from the deadly hunters! [tethysdust]