Attached to: Omega Squad
Atin, whose name means 'stubborn' in Mandalorian, has been the sole surviving member of his squad twice. The other three members of his first squad were killed on Kamino during a live-fire exercise while trying to rescue him, and he lost his second squad on Geonosis.
As the only Omega trained by Walon Vau instead of Kal Skirata, Atin didn't quite fit in right away and he tends to think differently than his squad members. Atin's specialty is comms and tech. He loves exotic weaponry, and especially favours the Trandoshan LJ-50 concussion rifle. Atin is also very attuned to his surroundings, noticing the smallest things.
Atin is distinguished from his clone brothers by a large scar on his face; his "souvenir of Geonosis".
Atin @ Star Wars Wiki
Tough! - Karen Traviss explains the background behind the Mando'a word atin