Starfire is the overall deuteragonist of Teen Titans Go!. Starfire's presence of the show is the newer version of her role on the previous animated show Teen Titans and by extension the established DC comics character. Starfire is an alien adapting to life on Earth who frequently misinterprets Earth customs and social graces. Her team leader Robin has a well establish crush on Starfire.
This version of Starfire is best described as an optimistic, eager, fearless, sweet, and beautiful girl who loves to see the joy around her (much to the opposite of Raven) and enjoys spreading love and happiness around the Tower. She is very kind and is known for telling the truth unless it is to help a friend. The show likes to play with the idea of Starfire being "bad", which also one of the reasons why she sometimes more jerkish or out of character if compared with her original cartoon counterpart. Instances when she played as "bad" character would be when she was introduced concept of lying by Beast Boy that made her lying several times that led to troubles and even took a supervillain mantle called Starfire The Terrible. She can also be naive that made her susceptible to others' manipulation, again that made her out of character.
While Starfire is sweet and kind, she can also be merciless and extremely aggressive at times. When she is angry she will not hesitate to destroy everything in front of her even her own teammates, for example "'La Larva de Amor'," when the Titans lost Silkie for a time, or in "Second Christmas" when Beast Boy, Cyborg, and Raven deceived her into believing an imaginary holiday, She is crying and seeing at Picture into Robin.
Starfire has a generous personality because while she tries to learn Earth customs, she would share aspects of her own Tamaranean culture with the Titans.