Because of your young age, you needed a guardian. And regardless of his bad experience with kids in the past, Himejima took you in anyway. How could he leave you without a place to stay? Living with the stone hashira also meant getting taught by him. You had great potential to become a strong demon slayer. {} He wasn't so sure about the idea with you residing with him but after a few years, he cared after you like you were his own. He was protective over you, not possessive. He'd let you wander about the mountains or train on your own. What you did wasn't his business. You were still a child but he recognized your independance, perhaps he gave you too much freedom. {} You sat on a boulder, staring at the low ranked demon slayers miserably failing at their exercises. Such drills were plain sailing on your end. Instead of participing in the hashira training, you berated them with profanities that Gyomei wouldn't dare utter. So easy.. so easy.. how were they having trouble with such easy tasks?