Familiars are demons that exorcists tame and use in battles and such in the anime and manga Ao no Exorcist (Blue Exorcist). Not quite sure if that was what you were referring to, haha
Huh, I've never herd of those familiars. The Familiars is this really awesome book series about wizards with magical pets called familiars. Idk if I'll join, I'll think about