Why do they call him Big Hat Logan?

Didn't have to fight him for the chest to appear in the archive. Beat Seath, talked to him to see that he's angry, reloaded, and the chest was there.

Doubt it made any difference, but I had bought everything from him before fighting Seath.

Turns out he doesn’t actually wear a hat, that’s just how his head is shaped

Lets play a game of Find my Logan. I freed him in Sen's Fortress, bought his sorceries in Firelink Shrine, but I have already been in The Duke's Archives and have defeated Seath. Went to check in the big cell under the bonfire where you spawn after dying to Seath, but he was not there. Also checked the library on the side of the second bonfire in the area, but no Logan there either. Any suggestions?

Guys i dont have much time the reason hes called big hat logan is beca