"that person" definitely Kuzunoha!!! I will definitely be happy if it's Acchan but the way she suddenly gone just for that moment feels like they didn't destined to meet. There's other manga that used plot "Seimei turned against humanity for killing his mother" or something, if this Seimei also wish to reunited with her that's probably the reason he refused to stay in a world where they can't meet.
"that person" definitely Kuzunoha!!! I will definitely be happy if it's Acchan but the way she suddenly gone just for that moment feels like they didn't destined to meet. There's other manga that used plot "Seimei turned against humanity for killing his mother" or something, if this Seimei also wish to reunited with her that's probably the reason he refused to stay in a world where they can't meet.