Muzan and Kagaya were still very young, around five years old. They were both born ill, but loved to play, Muzan was very smart, but had troubles with his health and got sick often, but he was very smart for his age, Kagaya however, was autistic, he still hardly spoke and showed what he wanted to with body language and was developing a bit slower, but he was observant, and smart in his own way., today they were playing in the living room with a ball