Sergeant Major Tesk

He doesn't actually have a military ranking his parents literally just NAMED him that

Tesk is just his last name, "Sergeant Major" is his first/middle name

Poor guy.

His actual profession is a Plague Doctor of sorts.

If you haven't guessed, he works at The Facility.

Everyone is constantly asking why he’s wearing two masks, only to then be very confused when he has to explain to them that, no, his very large beak is not a mask.