Sentinel Prime|Human

Pre-film

One of the first ever Cybertronians created by Primus, Sentinel served as the chief advisor to the original 13 Primes. This position earned him respect from his fellow Cybertronians, but Sentinel became increasingly power-hungry and envious of the Primes and their glories. In a bid for more influence, he arranged a secret meeting with Quintesson Commanders, which led the Primes to seek Sentinel's intel. However, this meeting was a trap set by the Quintessons, and in the ensuing conflict, Sentinel betrayed the Primes and played a role in their downfall. Stabbing Nexus in the back, beheading Megatronus Prime when the Quintessons dogpiled him, using Nexus' cannon to shoot Solus Prime into a rock, and shooting Zeta Prime in the head. Before Sentinel could claim the Matrix of Leadership for himself, Primus deemed him unworthy of it due to his power-hungry nature, causing the Matrix to vanish. Following this, he claimed the transformation cog of Megatronus for himself, which augmented his power to the level of the Primes. Only Alpha Trion managed to survive his greed, while the High Guard, the personal army serving the Primes, reject him, his attempts to claim power, and went into hiding on the surface after witnessing Sentinel's betrayal as he slaughtered the Primes. They continued to fight in the shadows, working to sabotage Sentinel, as they came to believe that might makes right instead of unifying all of Cybertron. After his initial attempt to seize power failed, Sentinel relocated Cybertronian society underground and established a new regime, arrogantly claiming the title of Prime for himself. He converted all existing Cybertronians to his followers, with the exception of the High Guard, who continued to oppose him from the shadows. To consolidate his power, Sentinel removed the transformation cogs from all future Cybertronians before they could come online, stripping them of their species' natural ability to transform.

Film 1

After another secret meeting with the Quintessons and failing to find the Matrix once more, Sentinel returned to Iacon to announce his failure before announcing the upcoming Iacon 5000, where bots who would transform would race to show their stuff and gave all working cog-less bots the day off to see it. During the race, Sentinel noticed two miners named Orion Pax and D-16 using jetpacks to compete as racers. The two lose the race and are taken to Sentinel to face repercussions for their recklessness, only for Sentinel to falsely congratulate them for their efforts, offering them higher positions in return. However, he soon leaves to go out and find the Matrix once more and the pair were eventually assigned to waste management by one of Sentinel's enforcers Darkwing. Unbeknownst to Sentinel, Orion, D-16, B-127 and Elita-1 would find a distress beacon from Alpha Trion, and eventually make their way to the surface to locate him via coordinates on the beacon and they soon end up learning the truth about him after locating Alpha and seeing him giving some Energon to the Quintessons, who came to the planet to collect them as part of their arrangement with Sentinel. When the Energon presented proves to be inadequate, the Quintesson High Commander nearly tears apart Sentinel, who talks him out of it by promising to get more Energon by extending the miner's work hours to meet their demand. However, Sentinel's second-in-command Airachnid ends up sensing the main quartet of bots and warns Sentinel of their presence.

Film 2

Soon, Sentinel and his forces locate them in Alpha Trion's cave, but the four bots (who were given cogs to transform and a chip containing evidence of Sentinel's treason by Trion) manage to escape while Alpha stays behind to hold off their forces to buy them some time. Trion is taken back to Sentinel at Iacon and starts to intimidate him to sell out the bots, but Alpha Trion rebukes him every step of the way, warning Sentinel that he will end up failing. Fed up with this, Sentinel kills Alpha Trion and orders his followers to locate the four bots, which they eventually do when they find them in a hidden area on the surface where the High Guard has been hiding. With that in mind, Airachnid and the Death Trackers manage to lay down an ambush, killing several of the High Guard members and destroying the chip exposing Sentinel's crimes. Airachnid and the Death Trackers took the opportunity to capture half of the surviving High Guard members (including D-16, Starscream, and B-127) and taking them to Iacon while leaving the other half of the High Guard (including Orion, Elita-1, Soundwave and Shockwave) for dead. Delighted that the High Guard is finally defeated, Sentinel mocks them for their fruitless attempts to expose him. Sentinel then announces as part of his next move to cover his tracks, he will come up with a false story that the High Guard members are plotting with the Quintessons and that he will publicly execute them. He insults B-127 for calling out this lie and shows his arrogance by claiming “the truth” is what he makes. When D-16, who has been feeling embittered from Sentinel's corruption ever since he learned of it, stands his ground against the evil tyrant, an unmoved Sentinel retaliates by burning the symbol of D-16's favorite Prime, Megatronus, onto his chest and reveals that he murdered Megatronus and stole his cog for himself. When D-16 got back up, Sentinel decides to kill him.

Appearance as human

Sentinel Prime is a guy with a height of 1 m 88 cm. He has fair skin, blue eyes, and short blue hair with a golden streak escaping. He wears a blue shirt, a gold tie, a blue jacket with gold piping, blue trousers and navy blue shoes.

Personality 1

Initially, Sentinel was presented as a humble and well-loved leader who was the living manifestation of peace and prosperity. He was also shown to be a courageous and encouraging leader, always praising the hard work of the miners who collected Energon. He was also respectful towards both Orion and D-16, after the two impressed him during the Iacon 5000 race event, and even personally thanked the two for inspiring the miners and invited them to his personal quarters so they can be patched up. But it would all turn out to be a facade, in truth, Sentinel was actually an evil, manipulative, self-serving, fraudulent, tyrannical, egotistical, deceitful, treasonous, black-hearted, and treacherous overlord who willingly sold out his own race to the Quintessons to claim power for himself and giving away their Energon to the Quintessons. He was even willing to have the miners work triple shift to collect Energon, despite the high risk of them potentially dying. He also was aware of how much of a power-hungry monster he actually was, as he brags about wanting to be a king and have power over others. He had also showed sadistic tendencies, as he personally killed each Prime in cold blood and brutally carving Megatronus' insignia into D-16's chest with a blowtorch, simply to mock him and the memory of his idol hero, showing he has no remorse for others.

Personality 2

Sentinel had lacked any form of empathy towards all other Cybertronians. He was also quite cowardly, as he would hide behind his troops instead of fight someone head-on, even when he was fully capable of holding his own in a fight. Ultimately, Sentinel ends up outing himself as a despotic, arrogant sadist; who cares for no one but himself. Despite all that, Sentinel is not without fear like when the Quintessons torture him for not bringing him enough energon and promises to get the rest for them. Then when his crimes and confession are being broadcast across Iacon, he watches in terror and shock as the people have now turn against him. And after getting beaten by D-16, he is reduced to begging for his life.