Kix

We all know Kix as the medic from the 501st who was dedicated to protecting the lives of his fellow Clone brothers. He had no issue destroying the enemy, made clear with his amazing tattoo of "A Good Droid is a Dead One" on his head. This poor guy, though, eventually spent 50 years essentially frozen in time but not after finding out about the chips in all of the clones' heads and being tortured. Understandably, he's left shell shocked and sad he couldn't save his Clone brothers.