SETH!!!!
lol this translation from long ago(seth's desc or whatever)
"An unidentified boy who is feared under the name "Assassin" by those who know of him. As if acting under the directions of someone, he appears before particular ability users and suddenly challenges them, but nobody knows his motives or exactly who he is. His whole background remains unclear.
As he catches mention of the name of the "Yato Princess", Linne, the expressionless assassin's face suddenly becomes cloudy.
Ever since that day, without being ordered to by anyone, he wanders the town in search of traces of the yet unseen princess."
and his desc on the matches, sounds like he's linne's boyfriend from long ago lmfao. and linne broke her promise and found another guy(hyde) lololol