All he knows about her is she's another student from Hope's Peak, the SHSL Soldier. That makes her someone he owes and someone to take care of. She was in the 78th Class, so that also makes her his kouhai. That matters more than the fact that she's kind of suspicious. Reminds him of Peko. She also actually knows what happened at Hope's Peak, and he'll be asking her about it when he's convinced she won't have a panic attack over it.
MUKURO