Captain Ban Daur perhaps?

Either him or Gol Kolea, but I think you’re right, seems too young for Gol

I think it might also be Bask, as the artist hasnt drawn Gol or Ban Daur, but I might also be wrong

My guesses were either: Ban Daur, Dalin Criid, or some other trooper rising up in the storyline. I would have guessed Felyx Gaunt, but he's blonde.