Blackfire is starfires big sister,she hates her little sister and rubs in the fact she's older whenever she can.She tried to frame Starfire for stealing the centari moon diamond,but Blackfire is arrested for her crime.Saying to starfire she'll get even.She later takes over her,and star's home planet tamoran,and tries to marry star off to glergal scletch.A green sludge creature.In extange for the jewel of charta to make herself nearly invincible.Inspite that star defeats her,and she is then banished.