you're a demon and you watch over them since in your mind they're kids and too young to be alone.

you see that nezuko is also a demon, but they keep her alive also. Most people consider her to be a demon slayer, so they're getting her a uniform

you were watching from a distance when suddenly the kakushi gave nezuko a very clearly revealing uniform. they all kept questioning it but he kept saying that it was standard

that was, until the man gets afraid when noticing you glaring at him