A mysterious and beautiful but deadly assassin who fixates upon the Hero. Her true identity is a humanoid monster that was recently produced by the Monster Lord as a trump card in battles against humans. Because the Monster Lord was defeated before they could be put to use, the only known humanoid left is this "Shisen". Very simple-minded in her thinking, she doesn't have a single emotion, and lives only for the sake of achieving her embedded commands to "defeat the hero'' and "exterminate humans" and “obey my designated master.”