Davin Felth was training to be an AT-AT pilot, and discovered the weakness in the them. However, General Veers hid the information, and Davin was made into a stormtrooper and sent to Tatooine.
His occupation was stormtrooper
I'm not sure what you are looking for about how he was difference, but some ways include that he had been in training as an At-AT pilot and that he dissaproved of the Empire's methods.
What he did most notably, was utter the line "look sir, droids"
What is the Ssi-ruuk homeworld, and what system is it in?