Seku is a character in the Devil Children series of games.
Devil Children Fire/Ice BookEdit
The older sister of Rejiinu. She tracks down Jin after learning about someone suspicious with her sister. Once she hears that he was helping Rejiinu she decides to give him info as thanks and mentions the Ginnungagap as the place between the worlds of ice and fire and the war between both worlds. She also decides to help him bypass the magical devices that protect the Ice Apostle's Castle.