Starline was calm, theatrical, and sophisticated most of the time, exuding an arrogant sense of pride in his intellect and abilities. Rather formal in behavior, he often addressed others as "gentlemen". However, he was also ruthless, sinister, and cruel, as he was willing to force Dr. Eggman to be a part of an evidently painful procedure against his will to bring him back to normal. Showing contempt for weakness, he possessed an incredible drive, as seen how he kept searching for Eggman despite becoming quite ill from sleep deprivation in the process. Despite possessing a calm demeanor, his patience did have its limits; after spending time with Eggman, Starline began showing occasional bouts of anger and frustration primarily directed at Eggman's imperfections, stubbornness, and refusal to listen to his reasoning. Ultimately, Starline would lose his patience after being fired by Eggman. In this state, he had proven himself emotionally unstable and prone to angry rants.