Ornis

A teacher at Hijirigasaka Academy. Initially assumed to be a human, it is revealed that Mamoru Sakazaki is actually a god like being called Ornis. He is intent on killing Basara, who he believes reached beyond his stature through earning Hasegawa's affection, and believes that killing him will bring Hasegawa back to heaven. After using Kurumi as a hostage to prevent Basara from attacking, he then succeeds in cutting off Basara's sword arm. However, this causes the sword to react and release the spirit of Brynhildr, one of the most powerful Valkyries. In this form Basara's arm grows back, his hair changes color and his right eye glows. He moves so fast that Sakasaki cannot even see him, and he cuts off the top of his foot using Banishing Shift, which he could earlier only use as a counter, not as an attack. Basara attempts to kill Sakasaki but Hasegawa intervenes. She then reveals that she always knew that Ornis has replaced the real Sakasaki. Using her full power, Hasegawa kills Ornis and has Basara take the credit for killing the god.