The Qwaser of Stigmata(2010)

Seikon no Qwaser

When Mafuyu Oribe and her adopted sister Tomo rescue a strange wounded man, they have no idea what they're getting involved with or what the consequences will be. Alexander Nikolaevith Hell is an Iron Qwaser, one of many opposing factions of super-warriors who can each draw upon the power of an element and wield it as an almost unstoppable array of weapons. And unfortunately for Mafuyu, Alexander's faction is there to gather the mystical relics known collectively as the High Circuit, which puts her friends, family and school at ground zero in a battle for the fate of all mankind! But there's an even more disturbing twist, as Qwasers require a special liquid diet to manifest their powers, one provided by the women who serve as a Qwaser's partner. And THAT means that the nursing Mafuyu's already given Alexander isn't the only kind of nursing he needs!

(Source: Sentai Filmworks)