Even though Blackfire is Starfire's older sister, the two are polar opposites as Blackfire is grim, cunning, deceitful, immoral, sadistic and unremorseful who also has the optimum qualities of a villain. 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.