Familliar Poison is a acidic and life sucking poison imbeded in Sakura Kashima's familiars.
When a certain Sakura Kashima in one of the infinite parallel worlds that the Moon Kagari created learns of Kagari's existence, she sends familiars imbeded with a special poison as stated by Kotarou to work very well against life incarnate (Like Kagari). To Kagari, her ribbons, and Kotaou's aurora, the poison has the ability to weaken its effects; when it touches flesh it will burn as if it was acid.
- Nameless Familiar: A small familiar who's body is made of poison, it is very quick, can speak and is the first familiar known to possess the poison.
- Deinonychus: Familiar created by Sakura Kashima in order to kill the Moon Kagari, has the appearance of a red and green rapter-like dinosaur with arms covered with feathers.
- Hound-Familiar: Dog-like familiars that may possess the poison or explode when killed.
- The poison used by Sakura's familiars may be the same poison mentioned by Lucia that the Earth will release when all of its life-force dries up.