Akiko is a princess Masahiro encounters in the second episode in the Imperial Palace after his coming of age and saves her when a demon attack her. She and Masahiro become good friends. Akiko is special because she is one of the few princesses to have the Kenki ability (the ability to see demons). Because of this many demons attack her often, so Masahiro must save her on various occasions. Later she will live with Masahiro in his home.

(Source: Wikipedia)