The story revolves around Shin and Dai sensei.Shin is a being who only craves destruction,but he has gotten bored over time -well, till Rin and Yuki appear.He deems them interesting and decides to let them live till he battles them for real.Dai shares a keen interest in them too and decides to support them in their goal to defeat Shin by training them.Although there seems to be a certain aura of mystery around Shin and Dai,Rin and Yuki will find the truth as the series goes on.