Transformers: 'Til All Are One

 is an American anime-influenced animated television series based on the Transformers toy franchise by Hasbro, airing exclusively on Paramount+. Each season consists of 8 episodes.

Premise
The series centers around Optimus Prime and his fellow Autobots of Cybertron as they protect humanity and other organic life forms from their evil counterparts the Decepticons, led by the tyrannical Megatron.

The first season centers around the Autobots and Decepticons on their last days of war on their doomed home world of Cybertron before seeking refuge on Earth.

The second season features the Autobots on Earth, where they earn new allies with humans (including U.S. army captain William Lennox and his protegee Izabella Morgan) who agree to keep their presence in secret, and also discover new breeds of Cybertronians on Earth; including a race of half-human, half-Cybertronian hybrids.

The third season is set after Unicron's defeat as Optimus reunites with his old mentor, Sentinel Prime, and his protege Hot Rod. Things get worse when the Autobot-Decepticon truce gets shattered by a rogue Prime, Megatronus, now known as the Fallen.

The fourth and final season involves Quintessa, the last of the creators of Cybertron, arriving on Earth under the guise of a foreign exchange student, planning on taking control of both Autobots and Decepticons. Things get worse when the ancient Predacons reawaken and side with Quintessa.

Main

 * The Autobots, a group of heroic Cybertronian Transformers (humanoid robots who can transform into machines, vehicles and other familiar mechanical objects) who battle against their evil counterparts the Decepticons for the freedom of all sentient lifeforms.
 * Orion Pax / Optimus Prime (voiced by George Newbern), the noble and chivalrous leader of the Autobots, and the last of the Primes. He transforms into a red and blue long-nose truck resembling a Peterbilt 379 (based on his vehicle mode in the live-action Transformers films).
 * Elita-One (voiced by Maria Canals-Barrera), Optimus's romantic partner, the Autobots' female leader, and a triple-changer who transforms into a pink limousine resembling a and a Harrier jump jet.
 * Arcee (voiced by Jennifer Hale), a courageous female Autobot who transforms into a blue motorcycle resembling a Kawasaki Ninja 250R.
 * Bumblebee (voiced by Josh Keaton), a young Autobot scout who transforms into a yellow and black sports car resembling a modern Chevrolet Camaro (based on his vehicle mode in the live-action Transformers films).
 * Ratchet (voiced by Jim Meskimen), a veteran Autobot medic and scientific genius who transforms into a white and red ambulance resembling a Ford E-350.
 * Bulkhead (voiced by Kevin Michael Richardson), a husky and cantankerous Autobot warrior, and a devoted follower of Optimus Prime who transforms into a green SUV resembling a Lamborghini LM002 and is based on the Transformers: Animated character of the same name.
 * Sentinel Prime (voiced by Ross Marquand), Optimus's long-time mentor and predecessor as leader of the Autobots. He transforms into a red and black fire truck resembling a Rosenbauer Panther (based on his vehicle mode from Transformers: Dark of the Moon).
 * Hot Rod (voiced by Nadji Jeter), Sentinel's protege, and a young Autobot who transforms into a red and orange sports car resembling a Lamborghini Centenario (based on his vehicle mode from Transformers: The Last Knight).

Supporting characters

 * Izabella Morgan (voiced by Melanie Minichino), a teenage human who is a friend of the Autobots. She is a young adventurer, and scientific genius with an IQ of 300 who specializes on Cybertronian technology on a way no other human can. She was orphaned at the age of 6 after her parents, the founders of Kinetic Solutions Incorporated (K.S.I.), were killed by a failed experiment started by Silas.
 * Sapphire Prime / Chloe Evans (voiced by Dove Cameron), Izabella's best friend, and a teenager who is revealed in the near end of Season 2 to be a half-human, half-Cybertronian hybrid. Learning of this, Chloe also learns of and embraces her Cybertronian identity as Sapphire Prime.
 * William "Will" Lennox (voiced by Matthew Mercer), Izabella's mentor and caretaker, and an U.S. army captain who is allied to the Autobots.
 * The Dinobots, a sub faction of Autobots who transform into mechanical dinosaurs or similar prehistoric animals.
 * Grimlock (voiced by Travis Willingham), the headstrong, but loyal leader of the Dinobots who transforms into a grey, red and gold mechanical Tyrannosaurus Rex which can breathe fire, and he wields a flaming sword in robot mode.
 * Wave (voiced by Laura Bailey), the only female member of the Dinobots, and their second-in-command who transforms into a red and blue mechanical Spinosaurus, and wields a flaming spear. She is also a professional swimmer in both her robot mode and Dino mode, and a mechanical genius.
 * Swoop (voiced by Jason Spisak), a Dinobot spy who transforms into a grey, red and gold mechanical Pteranodon and wields a flaming flail.
 * Slug (voiced by Dave B. Mitchell), a Dinobot enforcer who transforms into a grey and green mechanical Triceratops and wields a flaming club.
 * Maximals, a sub faction of Autobots who transform into mechanical animals.
 * Optimus Primal (voiced by Ron Perlman), the leader of the Maximals who transforms into a silverback gorilla.
 * Airazor (voiced by Ming-Na Wen), a female Maximal and the second-in-command who transforms into a fire-breathing peregrine falcon.
 * Cheetor (voiced by Nadji Jeter), a Maximal scout who transforms into a cheetah.
 * Rattrap (voiced by Patton Oswalt), a Maximal demolition expert and spy who transforms into a rat.
 * Rhinox (voiced by David Sobolov), a Maximal tech expert and enforcer who transforms into a white rhinoceros.

Antagonists

 * The Decepticons, the Autobots' evil counterparts and main enemies, and a faction of villainous Cybertronian Transformers who seek to restore Cybertron by terraforming Earth.
 * Megatronus Prime / The Fallen (voiced by Michael Emerson), the founder of the Decepticons, and a former member of the Dynasty of Primes.
 * Megatron (voiced by Fred Tatasciore), the tyrannical leader of the Decepticons, and captain of the warship Nemesis. He transforms into a silver and purple Cybertronian jet, which is based on his vehicle form in the first live-action Transformers film.
 * Airachnid (voiced by Mary Elizabeth McGlynn), a devious female Decepticon who transforms into a black helicopter resembling an RAH-66 Comanche, though while she is in robot mode, the helicopter's rotors can unfold and extend into long legs akin to those of a spider. She can also shoot spider webs from her wrists, produce a highly corrosive acid, and telepathically control the Insecticons.
 * The Insecticons, Airachnid's trusted minions who transform into large mechanical bugs, including beetles and wasps.
 * Barricade (voiced by Keith David), a former Decepticon scout who was promoted as second-in-command, he transforms into a black police car resembling his live-action Transformers film counterpart.
 * Shockwave (voiced by Steve Blum), an emotionless one-eyed Decepticon, Megatron's first lieutenant on scientific endeavors, and the creator of the Predacon clones, whose vehicle mode is a purple Cybertronian tank resembling his third live-action Transformers film counterpart.
 * Soundwave (voiced by Fred Tatasciore), an expert Decepticon and hacker who transforms into a blue UAV drone aircraft resembling an MQ-9 Reaper. While he is the most intellectual of the Decepticons, he speaks the least among them, and most occasionally quotes: "Soundwave superior. Autobots inferior.".
 * Laserbeak, one of Soundwave's personal minions, and a vulture-based Decepticon drone.
 * Ravage, one of Soundwave's personal minions, and a wolf-based Decepticon drone with a turret in his back.
 * Breakdown (voiced by John DiMaggio), a powerful and brutish Decepticon warrior who transforms into a blue military truck resembling an Oshkosh Sandcat equipped with a missile turret on the roof.
 * Unicron (voiced by David Kaye), Cybertron's fallen god of chaos and brother of Primus.
 * Heralds of Unicron, a group composed of enemies of Cybertron who faithfully serve Unicron. They consist of:
 * Starscream (voiced by Steve Blum), a former Sky Commander of the Autobot Energon Seeker army on Cybertron who became Megatron's second-in-command on the Decepticons until, after taking over leadership following Galvatron's death by Metroplex's hands, was overthrown by the resurrected Megatron and banished from the Decepticons. Relocating to Earth after the events of Season 1, Starscream plots to eliminate Megatron and take his place as leader of the Decepticons again. Also in the season, Starscream transforms into a jet based on a General Dynamics F-16 Falcon.
 * M.E.C.H., a terrorist organization of mercenaries and thieves who seek technology (including from Cybertron) to impose a new world order. However, by the end of season 2, M.E.C.H.'s technologies and weapons become sentient and part of Unicron's forces. The organization consists of:
 * Leland "Silas" Bishop / Nemesis Prime (voiced by Clancy Brown), the ruthless founder and leader of M.E.C.H., and a former colonel in Special Operations of the United States military who went rogue after being dishonorably discharged for endangering innocent citizens with his experiments, one of which resulted in the deaths of Izabella's parents. In the climax of "Turf Wars", Silas pilots a M.E.C.H. super armor to battle both Autobots and Decepticons, until he is gravely wounded by a blast from Shockwave. In "The Human Factor", Silas's mind and broken body are inserted in the remains of a destroyed Nitro-Zeus, for which he adopts the alias of Nemesis Prime. But the corrupted Energon within his new form exposes him to Unicron's influence, forcing Silas to kill his own men and become one of Unicron's heralds.
 * Harold Attinger (voiced by John DiMaggio), the former manager of Kinetic Solutions Incorporated (K.S.I.) who is discharged and arrested for conspiring against the government with his company's technology. He soon escapes prison and joins M.E.C.H. on their campaign against the Cybertronians in exchange of the means to regain control over the K.S.I.. In "The Human Factor", he helps insert a severely injured Silas in the remains of Nitro-Zeus, turning him into Nemesis Prime. He and the M.E.C.H. soldiers are however betrayed and killed by Silas, who falls under influence of Unicron.
 * Quintessa / Tessa Quinn (voiced by Ashley Johnson), the last of the creators of Cybertron who believes that Cybertronians have been operating insufficiently, and has decided to "unite" them and rid them of their emotions. To ease her objective, she takes the form of a teenage exchange student known as Tessa Quinn as she tries to get somewhat close to Izabella.