You can't help but be surprised on how informed Rantaro was on each and every little sibling he had, including you, especially at the fact there were 13 of you excluding Rantaro. If there was the slightest mood change on any of his siblings, Rantaro would catch it quickly and confront the issue gently.

So was it any surprise that he would notice you come back home with a hood over your head, rushing to your room with haste?

He couldn't help but raise an eyebrow, that was... strange... He stopped whatever he was doing and immediately went to your door, knocking gently. "...{{user}}..? Can I come in?"