Transformers: EarthSpark

• Twitch Malto (voiced by Kathreen Khavari) – An inquisitive and competitive Terran Transformer and Robby's partner. She transforms into a flying Cybertronian drone.[9]
• Thrash Malto (voiced by Zeno Robinson) – A fun-loving and impulsive Terran Transformer and Mo's partner. He transforms into a motorcycle with a sidecar.[9]
• Hashtag Malto (voiced by Stephanie Lemelin) – An excitable media-savvy second-generation Terran Transformer. She transforms into a G.H.O.S.T. surveillance van.
• Jawbreaker Malto (voiced by Cyrus Arnold) – A sensitive second-generation Terran Transformer.
• Nightshade Malto (voiced by Z Infante) – A creative and scientifically-minded second-generation Terran Transformer. Nightshade is the first character in a Transformers cartoon to be identified as non-binary. They transform into a Northern hawk-owl.

• Optimus Prime (voiced by Alan Tudyk) – The leader of the Autobots. He transforms into a semi-trailer truck.[9]
• Bumblebee (voiced by Danny Pudi) – An Autobot scout who becomes the Terrans' mentor. He transforms into a yellow sports car with black racing stripes,[9] though it was shown he originally scanned a similarly colored compact car.
• Elita-1 (voiced by Cissy Jones) – The Autobots' second-in-command. She transforms into an all-terrain SUV.[9]
• Wheeljack (voiced by Michael T. Downey) – An Autobot mechanic and scientist. He transforms into a rally car.[10] Wheeljack was responsible for the drones that were scanned by Twitch who would later nickname him "Dad 2".
• Arcee (voiced by Martha Marion) – An Autobot soldier. She transforms into a muscle car.[10]
• Grimlock (voiced by Keith David) – A Dinobot warrior who transforms into a Tyrannosaurus.

• Megatron (voiced by Rory McCann) – The former leader of the Decepticons who has renounced his evil ways and has occasionally collaborated with Dorothy Malto. He transforms into an armored tiltrotor.[9] Megatron's renouncing of his evil ways have put him at odds with some of the Decepticons.
• Swindle and Hardtop (both voiced by Nolan North) – A pair of criminal Decepticon brothers. They transform into an SUV and a dune buggy respectively.[10] Swindle was detained and Hardtop's right arm was modified by Mandroid into a prosthetic replacement for his own. When Mandroid got away after his first fight with the Autobots, Hardtop was among those detained as he claims to Megatron that he was not himself. Swindle would later try to dupe Thrash and Mo into helping find Hardtop by stealing the Energon Scanner only to be repelled by Bumblebee.
• Skullcruncher  – A Croctobot who is in the possession of Mandroid and can transform into a crocodile. He was later put into G.H.O.S.T. custody after his defeat by the Maltos and Autobots.
• Soundwave (voiced by Sean Kenin) – A Decepticon who works with his cassette-bots minions. He transforms into a stealth Cybertronian aircraft and has a particular grudge against Megatron for renouncing his evil ways.[10]
  • Ravage - One of Soundwave's mini-cassette minions, taking on a cat-like robot mode.
  • Laserbeak (voiced by Jake Green) - One of Soundwave's mini-cassette minions, taking on a bird-like robot mode. He is the MC at the underground fight ring where Grimlock fights.
  • Frenzy (voiced by Tiana Camacho) - One of Soundwave's mini-cassette minions, and the only one with a traditionally humanoid robot mode. She is the only one of the mini-cassettes to have dialogue and can understand Ravage.
• Starscream (voiced by Steve Blum) – A Decepticon who transforms into a jet, formerly serving as the faction's Air Commander in the great war. After the war ended, Starscream was seen in the custody of G.H.O.S.T. by the time Soundwave was incarcerated. Blum reprises his role from Transformers: Prime and Robots in Disguise.
• Skywarp and Nova Storm (both voiced by Nicole Dubuc) – A pair of Decepticon Seekers forced to work for Mandroid. They both transform into jets. Skywarp can teleport.[10]
• Tarantulas (voiced by Alfie Allen) – A Predacon scientist who transforms into a spider. Residing under a Witwicky cemetery, Tarantula wants to be left alone and is shown to be caring when it comes to protoforms. He even gives Nightshade some advice regarding alt-modes.
• Breakdown (voiced by Roger Craig Smith) – A Stunticon who is one of a few Decepticons to renounce his evil ways and is close friends with Bumblebee. He transforms into a race car.
• Shockwave (voiced by Troy Baker) – The Decepticons' former chief scientist who has a vendetta against Megatron. He transforms into a Cybertronian 4-legged walking tank.
• Brawl – A Decepticon who was forced to fight in an illegal Bot Brawl for Energon to survive. He was later found to have been drained of his Energon alongside the other captive Cybertronians. This was caused by Mandroid who took his left arm.

• Shrapnel – An Insecticon who is in the possession of Mandroid and can transform into a stag beetle. He was later put into G.H.O.S.T. custody after his defeat by the Maltos and the Autobots.
• Bombshell – An Insecticon who is in the possession of Mandroid and can transform into a Japanese rhinoceros beetle. He was later put into G.H.O.S.T. custody after his defeat by the Maltos and the Autobots.

• Robby Malto (voiced by Sydney Mikayla) – A 13-year-old boy adjusting to his new life after being forced to move to a small town.[9]
• Morgan Violet "Mo" Malto (voiced by Zion Broadnax) – Robby's optimistic 9-year-old sister.[9]
• Dorothy "Dot" Malto (voiced by Benni Latham) – Robby and Mo's mother, who is a park ranger and ex-soldier. In "Age of Evolution" Pt. 1, it's revealed she has lost her right leg in the great Cybertronian war.[9]
• Dr. Alex Malto (portrayed by Jon Jon Briones) – Robby and Mo's father who is a college professor with a Ph.D. in Cybertronian History.[9]
• Mandroid / Dr. Meridian (voiced by Diedrich Bader) – A mad scientist and roboticist who seeks to destroy all Cybertronians. His real name is Dr. Meridian and was given the nickname "Mandroid" against his wishes by Thrash.[9] Mandroid had lost his original right arm in the Cybertronian war back when he used to work for G.H.O.S.T., and begins replacing his body parts with those of the Transformers he captures.
  • Arachnamechs - The spider-like creations of Mandroid.
• Mr. Smelt (voiced by Daran Norris) – A teacher at Witwicky Charter School.[10]

Short for Global Hazard and Ordinance Strike Team, this human organization has the goals of rebuilding the relationship between the humans and the Cybertronians.

• Executive Agent Croft (voiced by Kari Wahlgren) – A high-ranking member of G.H.O.S.T.[10]
• Agent Jon Schloder (voiced by Marc Evan Jackson) – A member of G.H.O.S.T. and the brother of Agent Croft.[10]

• Quintus Prime (voiced by Clancy Brown) – An ancient Cybertronian and one of the original Thirteen Primes created by Primus who serves as the scientist of the group. His artifact the Emberstone is responsible for bringing the Terrans into existence as he is shown to speak through it.