Marginal Prince: Gekkeiju no Ouji-tachi (2006)

The main character, Yuuta, is supposed to be the viewer's younger brother who goes off to study abroad on a small island in the Atlantic that can not be found on any map. The school he enters is called St. Alphonse Academy. The boys who study here are all "marginal princes" which appears to mean Princes of remote, frontier or border regions.