The Familiar Naruto!

Naruto, down on his luck since the end of the war, seeks out for retribution. He is then offered it by some unknown force until realizing that he might have bit off more than he could chew. Louise, finds Naruto as a Familiar, due to certain events, she proclaims Naruto as the strongest Familiar there is when she is met with a challenge. Naru/Zero/Fate-staynight.