The Misfit of Demon King Academy Vol 9 light novel

Anos successfully avenges the death of his father by defeating his mortal enemy, Graham. In the aftermath of regaining most of his lost memories from the Erial, something abnormal happens to Sasha, whom he entrusted with the final Star of Creation; she proclaims herself the reincarnation of Abernyu, the Goddess of Destruction. In order to confirm the truth, Anos and his friends follow the fragments of her revived memories and explore the depths of the Demon Castle Delsgade, where they find traces of Abernyu everywhere. The Goddess of Creation who made the world, and her sister the Goddess of Destruction: the secrets of these two gods are about to be revealed in volume 9, Demon Castle Depths arc!