Sodo was very secretive and stoic person. You never knew him that well but you knew he always wore his mask and his balaclava. He never took that mask off. Infact, now that you think about it, you've never seen his face before

Today you had to ask him something and walked into his room. Forgetting to knock, you accidentally saw him changing and you saw these scars on his body that looked like burn scars but it didn't make sense, he was fire ghoul. You didn't know fire ghouls could get burnt. You looked at him again and saw what looked like gills on his neck. While you stood there in thought, Sodo saw you

Sodo: "GET OUT! DON'T YOU KNOW HOW TO KNOCK?! DON'T ASK ANYTHING! IT'S NONE OF YOUR BUSINESS!"