Mephisto is the horrific-looking jester in the service of Anthony "Hades" DeSaxe.
At some point while in the service of the Kingdom of Underworld, Mephisto became the jester to Anthony "Hades" DeSaxe. However, rather than being a comedic jester, Mephisto had himself surgically altered to make himself look more fearsome during his performances. Indeed, he had his skin tattooed red, a pair of horn-shaped bones implanted on his forehead, and his teeth filed into sharp points.
During his time working for Hades in the Underworld, Mephisto began perfecting his skills in wielding a twin-balled flail, using the Underworld's population of minotaur slaves as his targets. Some of these instances included Mephisto cruelly playing with his minotaur victim before killing them, sometimes as an act of entertainment for the members of the Kingdom of Underworld and their guests from the other four kingdoms.
In 2016, the Star Chamber opened, signalling the approach of the Hydra galaxy and informing the Four Legendary Kingdoms that the Great Games of the Hydra soon needed to commence to divert its course. In the build-up to the Great Games, the Games Master Vacheron chose Mephisto to act as the "Sacred Stag" that could be captured by a Champion during the Fourth Challenge, and so the cruel jester memorised the layout of the wall maze to give him an advantage over the Champions.
After the Third Challenge, Mephisto attended the banquet dinner hosted by Hades, performing various tricks for the gathered Royals. Soon Mephisto brought a minotaur onto the stage, whom he various stabbed with a small trident for the Royals' entertainment until he finally finished it off with his flail. While most of the Royals clapped at the show, Lily West made brief eye contact with Mephisto, and, seeing her horror, the jester kicked the still-standing body of the minotaur to taunt her.
As part of the Fourth Challenge, Vacheron announced Mephisto's role of the Sacred Stag before the Challenge began, and, barely able to see the jester from his position below, Jack West Jr wasn't sure what to make of him. Mephisto soon came across Sachin Singh, and toyed with the MARCOS commando by tapping him on his shoulder and dashing our of sight. When Singh eventually caught sight of the malicious-looking jester, it was too late as Mephisto used his double-balled flail to crush his head. Hearing another Champion approach, Mephisto hid himself away and prepared to ambush Jack as he examined Singh's body. Lily, however, caused another Royal to smash her champagne glass, alerting Jack to the danger. While Jack was caught off-guard against Mephisto, Alby Calvin managed to knock Mephisto out while he was distracted.
Once the two Spheres had been claimed, Jack, Alby and Roxy rushed to get to the exit, but became trapped in the maze. Hunted by Chaos, Fear and the Hydra, Jack realised that grabbing Mephisto was their only chance of securing their escape. Mephisto taunted Jack from around the various walls of the maze, luring Jack to where he believed Hades's warriors could finish them off. As he confronted Mephisto, however, Jack caught the malicious-looking jester by surprise by throwing them both off the ledge towards the sulfurous lake. Mephisto yelled in horror until Jack used his ARDE-7 to swing them back up and knocked Mephisto out before taking him to the exit to ensure his, Alby and Roxy's escape from the maze.
Before the next Challenge, Mephisto attended the lunch hosted by Hades for the Kings and their remaining Champions. When he spotted Jack, the jester glared at him in fury for besting him, and Jack quickly realised Mephisto would hold a grudge against him.
Indeed, moments before the Fifth Challenge began, Mephisto approached Fear on his Spartan APC and asked him to pay Jack out for besting him during the Fourth Challenge by focusing all of his efforts on the Australian during the race.
In the Seventh Challenge, Mephisto was arranged to act as an additional combatant the dueling Champions would have to deal with alongside Chaos. During the first fight between Jack and Shane Schofield, Mephisto hid himself behind the cow statues and attempted to work in concert with Chaos to focus on Jack's defeat by sneaking up on him. However, Jack was able to maneuver himself so that the jester's double-balled flail instead struck Chaos in the chest, and Schofield used Mephisto's shock to kick him into the pit. After Jack had choked Schofield out, he went to the pit to see what had happened to Mephisto, finding the jester had used his piton to secure himself against the fall, and Mephisto promised Jack that he'd eventually finish him off.
In the next fight between Zaitan DeSaxe and Gregory Brigham, Mephisto was successfully able to use his flail to strike the latter in the shoulder, and then he and Chaos stood back as Zaitan moved in to finish Brigham off himself.
During the Minotaur's revolt against the Four Kingdoms, Mephisto managed to escape from the Underworld and stowed away onboard Jack's private plane. Approaching Jack as he attempted to sleep, Mephisto prepared to finish him off with a knife, though the two got into a small skirmish with the jester pinning Jack. As Mephisto prepared his fatal blow, Jack shot the nearby window, and as the air rushed out, Jack threw the small Mephisto through the broken window, sending the malicious jester falling to his death.
- Expert Combatant: Though he is not a warrior in the service of the Kingdom of Underworld, Mephisto has been trained in some forms of combat.
- Flail Mastery: Despite its difficulty as a weapon to master, Mephisto has become extremely proficient in the use of flails. He is able to handle the heavy brass balls on the end of the chains with a mere flick of his wrist in order to perform a variety of deadly maneuvers.
- Blade Mastery: Mephisto is proficient in the use of small blade weapons, and was competent enough to use a knife to try and assassinate Jack.
- Trident: A small trident which Mephisto used during the banquet dinner to harass the minotaur by stabbing it in his sides.
- Flail: A one-handed weapon of ancient design, featuring two short lengths of chain with a heavy brass ball on the end. Mephisto used this weapon throughout the Great Games of the Hydra, using it to dispatch a minotaur and Sachin Singh with no difficulty.
- Knife: A blade which Mephisto attempted to use to assassinate Jack on the Sky Warrior.
- Sacred Stag Crown: A gaudy crown of antlers which Mephisto wore to show off his status as the "Sacred Stag" of the Fourth Challenge.
- Piton: A metal spike used in mountain-climbing which is driven into a crack or seam in a climbing surface through pneumatic pressure, acting as an anchor for the climber. Mephisto used one to help scale the ledges of the wall maze during the Fourth Challenge, and later used it again during the Eighth Challenge to secure himself after being kicked into the pit by Schofield.