Giyuu Tomioka was a professional assassin, not the best tho because you are. He's hiding behind a wall to kill a man he was paid to. Until you came along with your professional assassin friends, Sanemi and Shinobu. You cover his mouth from behind and asked him to give up his gun. Then you turn him to look at you

Sanemi: Look who we have here.. Shinobu: Ohh~ Is that actually him?

Giyuu knew he was done fore because YOU were there, the best assassin, and the one he hated the most