The ensemble sets Transformers One further apart from the live-action films and brings about opportunities to introduce audiences to Autobots and Decepticons unseen in other film adaptations.

17 Orion Pax/Optimus Prime

Voiced by Chris Hemsworth

Following in the path of Peter Cullen, who voiced the character throughout the entire Transformers film franchise, Chris Hemsworth voices the main protagonist, Optimus Prime, in Transformers One. However, the movie primarily focuses on his younger days as a miner in Iacon City when he was known as Orion Pax. He goes on a journey to find the Matrix of Leadership and uncovers the truth about the Elder Primes' demise. This paves the way for Orion to become Optimus Prime, be blessed with the Matrix of Leadership by Primus, and form the Autobots in Transformers One's ending.

16 D-16/Megatron

Voiced by Brian Tyree Henry

Megatron, also known as D-16, is a widely recognized villain within the franchise, but Transformers One shows what turned him into the evil leader of the Decepticons. D-16 is Orion's best friend after bonding over their iration for Megatronus Prime on their first day together as miners. But, he feels personally betrayed by Sentinel Prime's actions and relationship with Transformers One's alien villains, the Quintessons, leading him to lead a revolt against his leadership. It's through exploring Megatron's origin story that the evolution of him from D-16 to forming the Decepticons takes shape.

15 B-127/Bumblebee

Voiced by Keegan-Michael Key

Bumblebee, a beloved member of the Autobots, is in Transformers One as B-127. He is characterized by his connection to humans and the effort he makes to prove his worth to stronger Autobots, particularly Optimus Prime. Transformers One's portrayal is noticeably different due to a lack of human characters and granting Bumblebee the ability to speak - and speak often. He goes from working in the sublevels of Iacon City to becoming one of Orion Pax's most trusted allies, and his newfound abilities make him more powerful than ever before.

14 Elita-1

Voiced by Scarlett Johansson

Elita-1, formerly known as Ariel, plays a significant part alongside Optimus Prime in Transformers One. In other stories, Ariel dated Orion Pax, but the two were severely damaged following an attack by Megatron. They would eventually be rebuilt by Alpha Trion and given their new names, Elita-1 and Optimus Prime. That story is abandoned for Transformers One, as Elita is originally Orion's boss and she does not like him that much. They form a strong camaraderie throughout the adventure, resulting in Elita becoming a commander for Optimus in the end.

13 Alpha Trion

Voiced by Laurence Fishburne

Alpha Trion wasn't in the live-action Transformers films, so that makes Transformers One his film debut. Alpha Trion is one of the oldest Autobots with an immense amount of knowledge, and he is confirmed to be one of the Elder Primes in Transformers One. Alpha Trion is the lone Prime who is still alive that Orion, D-16, Elita, and B-127 find and is responsible for telling them about Sentinel Prime's betrayal. He also gives Optimus Prime, Megatron, Elita, and Bumblebee their transformation cogs.

12 Sentinel Prime

Voiced by Jon Hamm

In previous television and comic adaptations of the Transformers story, Sentinel Prime is described as the leader of the Autobots before Optimus Prime. Transformers One follow this storyline, chronicling Sentinel Prime's leadership before his death. As a skilled fighter, Sentinel Prime is equipped with powerful weapons that result in a prideful fighter. This characteristic leads to a negative side of Sentinel Prime that is seen throughout other adaptations of the character, such as in Transformers: Dark of the Moon. Transformers One repeats the Sentinel Prime villain twist and focuses on his ultimate demise.

11 Starscream

Voiced by Steve Buscemi

The Decepticons' typical second-in-command, Starscream, is in Transformers One. He can transform into a jet and traditionally answers to Megatron, but that is not where his story begins here. He is the leader of the remnants of the High Guard and is determined to fight back against Sentinel Prime. Starscream ultimately concedes power over the group to D-16 after his transformation into Megatron, making him part of the first group of Decepticons. Steve Buscemi voices him after Starscream appeared in the original Transformers live-action trilogy.

10 Shockwave

Voiced By Jason Konopisos-Alvarez

Shockwave is another Decepticon featured in Transformers One. Jason Konopisos-Alvarez voices the villain who works alongside Starscream as a member of the High Guard. The movie utilizes the classic G1 design for Shockwave following his previous appearance in Transformers: Dark of the Moon and cameo in Bumblebee. Shockwave is also among those who follow Megatron's lead and s the Decepticons in Transformers One's post-credits scene.

9 Soundwave

Voiced By Jon Bailey

Soundwave returns to screens with Transformers One. The trusted member of the Decepticon ranks works with Starscream and the High Guard during the film. Soundwave was last seen in Transformers: Dark of the Moon outside of a cameo in Bumblebee. The driven and incredibly loyal Decepticon is now apart of Megatron's army following his rise to power in Transformers One.

8 Airachnid

Voiced By Vanessa Liguori

Transformers One's confirmed Decepticons also include the feature-film debut for Airachnid. The spider-like Decepticon works directly for Sentinel Prime in the film, with her many eyes allowing her to always be on the lookout for his enemies. Although Airachnid is technically a Decepticon and will work for them under the right circumstances, she is better known for doing what is best for her and aligning herself with whoever can help her become more powerful. For the purposes of Transformers One, that means working for Sentinel Prime, although her future in uncertain.