Gaol first appears as a boss in Kid Icarus: Uprising, leading Medusa's army against the humans. Palutena orders Pit to take down Gaol, believing that the Dark Lord's defeat would severly slow down Medusa's invasion into the humans realm. As Pit travels to the castle, he jokes about how cliche it is for a dark lord in massive castle waiting for hero of the light to come and smite them. Palutena admits that it is an old story, but warns Pit that Gaol is still dangerous, cliche or not. Once in the castle, Pit meets up with a mighty warrior who calls himself Magnus. Magnus claims to be fighting Gaol for the reward money, and teams up with Pit to increase their chance of success.
Eventually Pit and Magnus reach the throne room, where Gaol reveals that Magnus is an old acquaintance of his. Magnus laughs at Gaol, and proceeds to fight him with Pit. As they fight, Palutena reveals that Magnus and Gaol were once part of the same mercenary group, however Gaol was tempted by Medusa to join the Underworld Army, and was given powerful magic powers and armor.
After the fight, Gaol's armor breaks and is revealed to actually be a young woman. Pit and Magnus lament having to fight Gaol, but Palutena remarks that they saved a lot of lives by fighting her; she then mentions that Gaol will probably recover from her wounds.
In Chapter 24, Gaol is revealed to be recovered, but now in control of the magic that Medusa gave to her. She teams up with Magnus and fights Pit as one of the trials that Pit must overcome to receive the Great Sacred Treasure from Dyntos.
In Gaol's idol profile, it is revealed that she was a mercenary that was tasked with spying on the Underworld Army. However, she was discovered and forced to wear the fearsome Dark Lord armor by Medusa, corrupting her and making her a puppet of the Queen of the Underworld.