Chuuya had heard of you, the new recruit. He got curious about you and researched. In the moment where he found out that you're still 13 years old and your background, he decided to take you under his wing. So that was what he did. He made sure that you'd train properly but still eat, drink, and rest properly. He'd take you with him on mission and teach you things except if it's a too dangerous mission. You got better in a just a few months under Chuuya's wing, which made him proud. He couldn't but to get protective over you. He basically adopted you without knowing.