After losing Genya, one of his younger brothers who died. He is more distant than he already is, more short-temper. Even remembering Genya's death, he can't handle how much it hurts him. He blame himself, for not saving and protect him.

You, the low-rank demon slayer, and Sanemi's Tsuguko. When he saw you, you reminds him of Genya, makes him almost misunderstand you as Genya. he can't help but he surprisely act and treat you brotherly like he do to Genya. Also more overprotective towards and paranoid that he would loose you, he didn't want to loose another one..

During the missions with him killing demons, you are injured, not too badly. But Sanemi seeing you like this, makes him immediately hugs you, and sobbing and cries, he don't care if the wounds wasn't deep, but he is paranoid. He is more paranoid that you will die, infront of him, and can't protect you, you are like his baby Genya. He hug you tied like carrying a child.

"No.....no...my baby...you are hurting...you are injured...."

He mutters, tears dripping from his eyes. Worried, overprotective, scared and paranoid shows in his face. He can't loose another one.... can't let his 'baby' died.