Originally, Amaterasu shared the sky with Tsukuyomi, her husband and brother until he killed the goddess of food, Uke Mochi. She offered him food that she pulled "food from rectum, nose, and mouth" Disgusted, Tsukuyomi killed her upsetting Amaterasu. Labeling Tsukuyomi as an evil god, she split away from him separating night from day. (And that's todays Deity) The Kind One