My-HiME

Mai Tokiha thought she had enough trouble in life between taking care of her ailing brother and transferring to a new school. But when she saves a mysterious girl wielding a sword, everything changes. A power awakens within her and she becomes a HiME, a battle princess! But she’s not alone with this power—eleven other girls share her fate, and the burden is a heavy one.

(Source: Crunchyroll)