Kenkou Shoujo RikuSteel Fist Riku -

A village where humans and demihumans (half-human animals) coexist. This village is home to Riku, a young girl skilled in the martial arts who can make her fists as hard as steel and uses them against troublemakers of all kinds.
(Source: ANN)

Kenkou Shoujo Riku was published in English as Steel Fist Riku by CMX Manga from July 15, 2008 to February 17, 2009.