Maioka Shouko

Shouko is like a little sister to Kazuya -- she even calls him "big brother," and she does everything she can to make him happy. An extremely talented cook, she even invents her own recipes. Like Kazuya, Shouko has been recruited to fight the Evolutions; and as the war goes on, Kazuya begins to discover why Shouko wants him to be her "big brother" so badly...

(from Hirameki)