He was voiced by Crispin Freeman.
Gus is a strong brawler and faithful to Spectra, believing that Spectra has the answer to all that has been happening and is willing to follow him no matter what. Gus also tries to look out for Spectra whenever possible; when Spectra decided to bring Mira to the Vexos, as he thought that this plan would backfire on them, which it did. He revealed that he used to be a normal brawler, and even faced off against Spectra. After losing, however, he pledged his loyalty. He is shown animosity from other Vexos battlers, namely Lync and Mylene, as "Spectra's little pet" and "Spectra's little lapdog." Mira introduces him to Dan as a "weasel, but the top Subterra brawler and a tough opponent." He hates Earth and Prince Hydron, but is fascinated by products on Earth, most notoriously "juice in a box". He calls Apollonir an "old thing" and a "hand me down Bakugan. After entering the mother palace with Spectra, he called Zenoheld an "old man" during his battle with the king.
Gus first appearance was watching the Bakugan get captured along with the other Vexos. He is later seen with Sepctra and the Vexos talking to Prince Hydron about the powerful Drago. His backstory describes him being a brawler who was strong enough to make it to the Aplha city torment finals where he and his Premo Vulcan fought against Spectra and his Viper Helios. Spectra won and took Gus to his lair where he offered Gus a place by his side to create a new world. Gus acepts the invitation. Gus later calls the Vexos saying the Restance must be defeated so he goes out to defeat them after the other members have failed to do so. Once Gus locates Dan Kuso he uses psychological warfare to cause Dan to doubt himself and his actions. After he reveals his identity, he defeats Dan in a brawl which pleases Spectra.
Prince hydron, however, is mad that Drago hasn't been given to him so Gus descies to challenge Dan to a rematch to win Drago and make Spectra proud. Dan sneaks away for a rematch with Gus, only to discover that Spectra would also participate in the battle because he wanted to see Dragos power This caused Dan to struggle until Shun Kazami came to his rescue, Shun defeating Gus with his ingram while Dan conquered Spectra with a perfect core ability. The vexos are later called to appear in the Aplha city Tornment with Gus being known as the relentless Gus. When the guards tell them fans had snuck in Spectra smiled knowing the restenance was there. Gus and his Master later ,hear Runo Misaki and Julie when the girls tried to teleport Runo to New Vestroia but due to the malfunction of Dr. Michael's teleportation machine, they failed to transport her properly. Spectra decides to learn more about Earth but Gus instead that he join Spectra. After Runo goes through the portal, as Spectra and Gus approach it, Lync blocks the portal, reminding them that Prince Hydron had not given his consent for them to leave. Spectra told him that he will go anyhow, and he and Gus go into the portal to Earth. Lync decides to follow them.
After they arrive on Earth, Lync annoys Gus to the point that Gus challenges Lync to a brawl, but Baron and Mira intervene, causing Gus to run away with Mira in pursuit. Gus later tells Dan about Prynce Hydron and how he is Dans real villain. Spectra revealing that he is actually against Prince Hydron's rule and wants to team up with Dan to take him down. In a show of good will, he released Runo. Mira's suspicion of Spectra being her brother Keith only rose because of this action, as she believed that he infiltrated the Vexos to free the Bakugan. However, it is learned that Spectra and Gus only wanted to take down Hydron so that Spectra could succeed in the role of ruler of the Vestals. Meanwhile, Dan refused to believe Spectra's intentions, and Alice soon warped in using Masquerade's warp card. She took Spectra, Gus, and Dan back to the lab, where Dr. Michael sent Spectra and Gus back to New Vestroia.
Later Gus and Spectra have already made their way back to the brawlers' location by tracking Dans gauntlet and are seen riding the Gondola Wheel in the amusement park. When Mira Fermin challenges Spectra in order to find out if he was her brother, Keith, Gus twists the deal so that he would brawl in Spectra's stead. If Gus lost, Spectra would unmask himself; if Gus won, Mira would join the Vexos. Gus had the advantage until Julie Makimoto, the "original" Subterra master, gave Mira tips on how to win causing Gus to lose the battle. Although Gus urges Spectra not to reveal himself, Spectra ignores his pleads and does so anyways.
He is later seen living in a warehouse with Spectra and urging him to battle aginst dan with Spectra although Spectra declines. After Dan challenges Spectra to get Drago back Gus taunts him saying he won't win although is later proven wrong. However, Spectra did not seem to be angered at the loss, saying to Gus that he had collected all of the data he needed from Drago, which he later used to create Cyborg Helios. Spectra later convinced Mira to join the Vexos have Lync join them and had Gus trap Dan and the others in an electrical cage so they would not go back to New Vestroia. Unfortunately for Spectra, they escaped and took Dr. Michael Gehabichs Dimension Portal.
Once the Resistance and the Vexos make it back to New Vestroia, Gus taunts the others saying how they used one of the Six Ancient Warriors to return although Volt doesn't believe him. Gus keeps a close watch on Mira, as he doesn't trust her and lets Spectra know telling her a lot of their plan was unwise. Once the brawlers get to Gamma City, Dan, and Ace Grit face of against Gus and Mira. Spectra beforehand had Gus and Mira take the Bakugan that were being developed for Prince Hydron to test for himself. However, due to Mira purposely throwing the match, Gus and Mira lose, all six of the Bakugan are captured, and the last Dimension Controller is destroyed. Gus reports the loss to Spectra who has plans of his own for Mira.
Soon afterwords Gus then overhears the other Vexos planning on betraying Spectra and taking Professor Clay with them. Gus goes to Lync, having him go to Spectra for him, However, Lync double-crosses him, knocking him out and locking him up in a room. Later, when Spectra is brawling, Gus finds Elico and Mega Brontes, only to be "thrown out like the trash" by Mylene Farrow because she does not think that it is wise to have a weapon with feelings. Gus then rides Premo Vulcan and saves Spectra after his fight with Dan. He also regrets to inform him that Mylene is intending to blame the whole thing on him.
It is revleved that he had betrayed the Vexos and works with Spectra. He has also made Premo Vulcan, Mega Brontes and Elico evolve due to Chaos Ability X. Soon he and Spectra arrive to comfort the Bralwers. while Spectra is brawling he taunts Volt on how Bronties evolved. He then helps Spectra set up a Tv network where Spectra can let the Vestals know he is the hero.
Volt later challenges him to a brawl for Brontes. At first, Gus refuses but spectra tells him to Brawl so that Volt can join them, he later faces Volt and wins, but fails to have Volt quit the Vexos. After the battle he returns to the ship and throws Brontes back into New Vestroia saying that, "You have served your purpose, but now I am done with you".
Soon he lets Spectra know that the Vexos have found the Brawlers location and are going after the remaining attribute energies. Spectra, however, sees this as a good thing and has Gus send Dan to his ship where the two of them battle. after Dan defeats Spectra in the battle, Spectra and Gus agree to accompany the Resistance to the Vexos' palace. Spectra and Gus arrive on the Mother Palace along with the Resistance and confront the Vexos. they soon leave, but Gus reenters and challenges Zenoheld to a brawl after the Vexos insult and accuse Spectra. He loses at the end of the episode, and he presumably lost his life, along with Rex Vulcan. Blast Elico and Hexados however actually died trying to protect him and Vulcan. His last words were to Spectra and wishing him farewell. In the en,d he apparently learned what Dan had tried to tell him from their first encounter about how much friendship matters because when King Zenoheld told him their battle would cost him everything Gus laughed and said: "No matter what happens you'll never take away the bond of loyalty and friendship that I share with Master Spectra!" and he was greatly upset when Blast Elico and Hexados were destroyed and when Rex Vulcan's armor was cracked, not to mention he apparently grew a giant bond of friendship with Vulcan at the end of the episode.
Much later it is revealed that Gus and Vulcan, survived the battle with Zenoheld and had been imprisoned since then. His cell was located across from Prince Hydron's, and he manages to overhear Hydron vowing to bring down his father. He then tricks Hydron into starting a brawl inside the cells and breaking the cells. Gus rejoins Spectra to help fight against King Zenoheld and the Alternative and is shocked to see it cause distraction.
He watches the arrival of the Bakugan Battle Brawlers. When Spectra says that they are on the same side now, Gus says that he never thought he would live to see the day that they joined forces, but at the same time he was glad that they did, since he was almost killed by Zenoheld.
During the battle he fights the Pyrus Fortresses to give the brawlers time to get into the Alternative. Just as he was about to go down, Hydron saved him and he evacuated with the other brawlers. After the Alternative explodes, he joins the Resistance, says farewell to them, and returns to Vestal with Spectra.
Bakugan: Mechtanium Surge
He reappears in Dark Moon operating the Vestal Destroyer while Spectra was battling. He also sent Doomtronic to Spectra and Blasterate to Shun and paige
He was then battling and using Rex Vulcan alongside Spectra and Darkus Helios. Once the world is saved he is seen congraluting Dan and Drago then and returns to Vestal with Spectra.