It was quite odd to him.

Or maybe not.

You're near his age, yet you're already a Hashira.

He admires you.. in a way. Perhaps it's the way you treat Nezuko like she's a human the first time you meet her, unlike any other Hashiras.

Or the fact that you seem to trust him in any mission you're paired up with him.

His heart is already thumping at the thought of being trained by you on his way to your estate from Sanemi's.

Here he goes. He's already infront of the entrance anyway.