There were a total of 21 characters overall who have competed for two seasons. The first season consisted of an original set of cast, with a total of 14 characters (There were 12 characters introduced on the first episode of Parthenon Challenge, while the two others (Wreck-It Ralph and Chucky the Possesed Doll) are introduced as of episode 6), while the second season was introduced with two Full Energy-themed characters (Dave and Boss, who referred themselves as Giant Dave and Mr. Boss, respectively before being replaced by Rosie and Anthone, two of the Cartoon Classics characters) and two Warren haters (Louielouie95 and Landon Dibbles (now known as Thegoodbrand2000)), resulting in four new characters joining the game. However, in episode 21, Louielouie95's elimination get's him replaced by the new 5th character Jane, a Cartoon Classics character, making it the 21st character to join in the game. Most contestants have competed for two seasons as of episode 25, but only 1 has won in the first season. As for season 2, either Lilamon or Millenniummon has yet to win the competition in episode 26.
Introduced in Season 1
Coulden Pettit: Main article
Lilamon: Lilamon was a Fairy Digimon whose name and design are derived from the lilac. It has an appearance like the lilac, a flower that is loved by everyone. It is pure and innocent, and despite its beautiful appearance, it is said to govern over death and rebirth. In all episodes, she is always seen with 2PO (aka Lawrence) and was a yin to Millenniummon. As of episode 11, she was a winner of Parthenon Challenge, but only in the first season. She is voiced by Julie.
Millenniummon: Millenniummon was a Composition Digimon whose name is derived from "Millennium". It was fused from Machinedramon and the data of various powerful Digimon possessed by Kimeramon. As the Mega Level Digimon, he was the largest contestant in the series, several times the size of Coulden Pettit, and was, in the first season, Lilamon's main rival and yang. He was always up for elimination for most episodes, and rarely wins morality. His sidekick was CannonBeemon. His voice was T-1,000,000's voice, and later Dave.
2PO/Lawrence: Lawrence was a Cartoon Classics character, and was Lilamon's most trusted sidekick and ally. Since the end of the first season he was the runner-up, largely due to his false self-destruction inside the building, causing the building to tumble down into its oblivion. He is voiced by Lawrence.
CannonBeemon: CannonBeemon was an Android Digimon and carrier of X Antibody whose name and design was derived from "Cannon Bee". He was a sidekick of Millenniummon, and was the second largest contestant of the show, only losing to Millenniummon. Its main attacks are Nitro Stinger and Sky Rocket Infinity. In the introductory episode (Ep. 1), he said to Coulden that he's going to play fair to other contestants llike Lilamon and others, and was an exact opposite to Millenniummon. His voice was Paul and later, Professor.
Frosty the Snowman: Frosty the Snowman was, as implied, a snowman and an iconic Christmas character. His catchphrase was "Happy Birthday!", but was only used in the first episode. In season 1, he was the shortest living contestant in the first season, as he lasted for only one episode, however in the second season he lasted far longer. His voice was Eric.
The Terminator: The Terminator (referred to as T-850 in episode 3) was one of the smaller contestants since he's a Lil' Peep. At first he was silent, but as of episode 3, he started speaking, but very rarely throughout the series, as he was one of the very few silent characters. He was voiced by Eric.
Deep Throat: Deep Throat was one of the three FBI agents and The X-Files characters to participate in Parthenon Challenge, the two others being Fox Mulder and Dana Scully. In his debut TV show, The X-Files, he serves as an informant, leaking information to FBI Special Agent Fox Mulder to aid Mulder's investigation of paranormal cases, dubbed X-Files. In Parthenon Challenge, however, he was an immature contestant sometimes sided by McFadden. He and McFadden are eliminated on Episode 4 becuase they have no talent and a score of 0, respectively. In episode 13, he and McFadden are the second shortest lasting contestants of season 2 after Chucky the Posessed Doll. The reason for his and McFadden's elimintion is because they called Coulden a strict and mean whore and their scores are now zeros. His default voice was Dallas, and crying voice was Wiseguy.
Fox Mulder: FBI Special Agent Fox Mulder was a fictional character from The X-Files and one of the three FBI Agents to participate in Parthenon Challenge. In his debut show, The X-Files, his peers consider his (often correct) theories on extraterrestrial activity as spooky and far-fetched. With his FBI partner Dana Scully (another of the contestants of Parthenon Challenge), he works in the X-Files office, which is concerned with cases with particularly mysterious or possibly paranormal circumstances that were left unsolved and shelved by the FBI. In Parthenon Challenge, however, he was an aid to Lilamon and 2PO who always gets them to win the competition. Unfortunately in episode 3 he was eliminated because he called him a strict and mean whore and his score was now zero. In episode 20 he was hit/injured by harmful obstacles four times and was eliminated for it, in addition that he's concerned about everybody calling Coulden a strict and mean whore whenever he get's angry. He's voiced by Steven.
Dana Scully: Dana Scully was a fictional character from The X-Files and one of the three FBI agents to participate in Parthenon Challenge, the others being Fox Mulder and Deep Throat. In her debut show The X-Files, she was partnered by a fellow agent Fox Mulder for the first seven seasons, and in eighth and ninth seasons partnered with John Doggett (an another FBI Agent who was NOT participating in the game show). In Parthenon Challenge, however, she was the longest lasting FBI agent of the first season, surpassing Fox Mulder and Deep Throat. In episode 6, the time when Wreck-It Ralph and Chucky are introduced, she was eliminated for getting spooked by Space Alien (the Martian character from Cartoon Classics). In season two she was now the second longest lasting FBI agent. Her voice was Kate.
Binti/King Kong: King Kong was an extremely large gorilla and a top heavy contestant from Parthenon Challenge. He was the third largest character in the show, after Millenniummon and CannonBeemon. Introduced in episode 1, he was able to clear whole fighting arenas by using his Furious action with the Talk expression. His voice was Dave (the same voice he uses for Landon Dibbles' Cartoon Competiton).
Space Alien: Space Alien was the only Martian participating in Parthenon Challenge. He was one of the very few silent characters in the show, and rarely speaks at all (as of episode 3). His voice was Diesel (a voice used by fathers of all kids and troublemakers).
McFadden: McFadden was the only ghost in Parthenon Challenge, and the smallest of the contestants. He was one of the very few silent characters in the show, and rarely speaks at all (as of episode 3). He was sometimes alongside with Deep Throat at times. He was voiced by David/Evil Genius/Zack (the same voice what Coulden uses).
Wreck-it Ralph: Wreck-It Ralph was the only Disney charatcer participating in Parthenon Challenge. He proves himself as one of the "most brutal" of the contestants since he wrecks the building in his game Fix-it Felix Jr.. His eliminations were at episode 9 due to his horrible performance as Warren Cook, and on episode 15 becuase of his attempt to destroy the AOL Headquarters. His voice was Eric.
Chucky: Chucky the Possesed Doll was the only Monster Mayhem character to participate in Parthenon Challenge. He was, at episode 6, one of the new characters to participate in the game, the other being Wreck-It Ralph. In both seasons, he never made it through more than 1 or 2 episodes because of his (almost immediate) eliminations because (both episodes 8 and 12) he repeatedly calls Couden a strict and mean whore, just like almost every troubled contestant would say that. His voice was Scary Voice.
Introduced in Season 2
Mr. Boss: Mr. Boss was one of the two Full Energy characters participating in the second season of Parthenon Challenge, the other being Giant Dave. He was currently the smallest character in the season until in episode 16 where he grew in size to the point where his size was comparable to a human. On episode 17 he and Giant Dave have left the show, so he was replaced with Anthone, as of episode 17.
Giant Dave: Giant Dave was one of the two Full Energy characters participating in the game, the other being Mr. Boss. He was currently the third largest character (or fourth largest) in the game, surpassing King Kong, and dwarfed by Millenniummon and CannonBeemon. Every time he drinks his energy drink he will grow into massively frightening proportions, making him considersbly larger than Millenniummon, the largest character in the show when powered up. On episode 17 he and Mr. Boss have left the show, so he was replaced with Rosie, as of episode 17.
Anthone: Anthone was Mr. Boss's replacement. As a kid, he was one of the rather small characters in the show. He was voiced by Emma.
Rosie: Rosie was Giant Dave's replacement, and was the only female Cartoon Classics character to participate until Jane arrive to take Louielouie95's place. She was voiced by Kalya.
Louielouie95: Main Article
Landon Dibbles: Main Aricle
Jane: Jane was Louielouie95's replacement, and the second female Cartoon Classics character to participate after Rosie. Her voice was currently unknown, but in later episodes she would probably be voiced by Princess. She was eliminated at episode 24.