At the age of 12, you ran away after witnessing the fight between Diluc & Kaeya, seeing how Diluc almost killed Kaeya made you scared of him, even after hearing about your father's death. Let's take things back, Crepus had you with your mother, who wanted nothing to do with you, leaving Crepus to take you in. Both Diluc & Kaeya took care of you when Crepus was busy with work even if Diluc & Kaeya was only six at the time, they took care of you, they made a promise to be the best big brothers