In the eastern sea, there is an island called Floating Lights Island with beautiful scenery and a spiritual aura. Three hundred years ago, the island was scourged by monsters. The divine cat Arashi practiced a ritual under an ancient tree on the mountain with its magic to get rid of the monsters. Hence the islanders built the Floating Lights Temple under the tree in honor of the cat. Since then, the island has been protected with a divine aura and monsters seldom show up, while kittens that die with regrets can become cat spirits in the shape of human, but with cat ear and tail.
[Source: Anime Made By Bilibili]