During Tark's time as an Irken Soldier, Tark was observed as defective for lacking the destructive spirit that most Irkens have, but was never labeled as an actual "defective" due to this PAK being fully functional. 3 Irken years later, he was promoted to Irken Elite.
For a relatively long time, Tark had a bad reputation for literally trying to escape a mission that involved a disease. However, Tark's fear of diseases is actaully rooted to his early life; When Tark was born, a genetic disease was carried from one of the Irkens who's DNA was used to create him, and as a result, two years of Tark's smeethood were spent with Irken medical doctors attempting to this disease. This was especially traumatizing for him because, being just a smeet, he was low priority and would often spend days abandoned and alone. By this time, said doctors were ready to let him die, miracously, the cure was discovered on accident. From that day on, Tark would always fear finding himself with a similar disease.
Tark is, typically, a strict and focused soldier, forcing himself or others around him to follow orders exactly; Even often going to the extent of reciting an order word-for-word. This, of course, comes to the annoyance of others, also making him rather easy to be commanded. As a result, Tark can be a rather effective soldier; This behavior is considered proper to Irkens.
However, Tark isn't perfect. He's rather shy and speaks rarely, often only when necassary. In general, he tends to have some trouble interacting with others and will hesitate even when told to-he simply isn't a social person. He can, however, act friendly to someone he knows well; he simply has trouble warming up to people.
Noticebly, however, Tark's anti-social and hard attitude was much more noticeable after he survived mechanization, possibly fearing that this or another terrible fate would occur to him afterwards.