Witch Watch S01E20 - The Lost Wolf and the Stray Cat

Keigo can't use his immense strength unless he looks at a crescent shape. Nico sees that Keigo is sad, so she asks him to become the user for a ring that has "flying magic" sealed inside. If he can come to utilize it, he should be able to wield it as a weapon, so Keigo begins his training. One day, in the middle of training, Nemu visits and talks to him.