Book 1: Child of a Snake (Neji x Oc love story)

Kaiya was abandoned at the gate of Konoha by her father for her own safety. All she had was a scroll with a letter written by her mom and a snake necklace in a box with her name on it. She is brought to the hokage by Izumo and Kotetsu who orders Kurenai Yuhi to adopt her.