im gonna say something.. remember the first time yato saw hiyori.. he meets her eyes.. aside from the fact that she sensed his presence without any encounter, i think, he might have thought that she looks a bit like sakura in a way..
kou is the best brother possible like THINK ABOUT THE WAY HE TREATS TIARA NOW THINK ABOUT THE WAY HE WOULD CARE BABY MITSUBA AND NENE IM GONNA CRY