Though she is Starfire's older sister, the two are polar opposites. She also has the optimum qualities of a villain, and she is cunning, deceitful, immoral, sadistic and unremorseful. The two almost never get along well, except when Blackfire tricks Starfire into thinking she's being nice. Blackfire is constantly trying to, in some way, do away with Starfire, first with getting her arrested and then trying to marry her to an ooze alien. Blackfire loves fighting her sister and rubbing the fact that she is older and stronger in her little sister's face. The two of them are poster children for sibling rivalry. She has a very sarcastic sense of humor and always hurts Starfire's feelings. Blackfire is also quite vain and loves telling stories about herself. Blackfire is also quite pretty, and she knows it and uses it to her advantage when around boys. This is seen in the second episode, Sisters when she developed a crush on Robin upon meeting him and tried to gain his attention and affection, but this could also have been a ploy in further isolating her sister.