Father!Hellboy x Female!Child!Reader
You are a small elfling, pale white skin, long blond hair, and, unusually, big blue eyes (elves do not have blue eyes, thats what makes you an extraordinary case :)
He has found you, wandering around in the troll market, lost, hungry, cold, and little memory. He takes you in and you become the child of Liz and Hellboy, with Abe as your uncle.
But what happens when you meet a certain brother and sister, who know you and they want to take you?