Sentinel Prime (Transformers Film Series)

"Indeed I am! What you must realize my Autobot brothers, is we were never going to win the war! For the sake of our planet's survival, a deal had to be made... with Megatron!"

- Sentinel, revealing his true intentions.

"I bring you Cybertron, your home! And still you choose humanity!"

- Sentinel Prime

"Defenders of Earth: we have come for your natural resources to rebuild our damaged planet. When we have transported all we need, we will leave your world in peace. For such peace to exist, you must immediately exile the Autobot rebels you have harbored. NON-negotiable! Renounce the rebels. We await your reply..."

- Sentinel, threatening Earth.

Sentinel Prime is the true main antagonist in the live action film, Transformers: Dark of the Moon. He can transform into a fire engine. Sentinel Prime was originally an Autobot, but betrayed the Autobots and sided with the Decepticons so he can save Cybertron. The movie's title Dark of the Moon is a reference to him and his space bridge pillar technology that forms the plot. Sentinel's evil motives and selfishness towards both the Autobots and Megatron led to his own death.

Sentinel Prime is known for being the only antagonist in the live-action Transformers franchise in which Optimus Prime would have never been able to defeat alone, even with his best efforts.

Past
On the Planet Cybertron, there was a great war that practically destroyed Cybertron. Sentinel Prime wanted to recreate Cybertron, so he made a deal with Megatron that if he was to side with the Decepticons, Megatron would help him recreate Cybertron. Megatron told him to take his Pillars (machines that can teleport anything) to the planet Earth and they'll recreate Cybertron there. Sentinel Prime flew away in a ship called the Ark that carried hundreds of Space Pillars. Sentinel Prime was suppose to warp jump to Earth so he and Megatron could recreate Cybertron. However, before he could warp jumped, Decepticon airships dealt heavy damage towards the Ark, resulting in Sentinel Prime to accidently crashed landed on the dark side of the moon. This also resulted in Sentinel Prime entering in stasis lock.

In 1969, Neil Armstrong was secretly assigned to search on the moon and analyzes the crash. Armstrong claimed there were no survivors. Since 1972 no one went to the moon since, and was deemed above classified. Neil Armstrong decided to take the space bridge pillars from the moon, which were then stored in secret by the government which became a law that no one is to know of the alien technology. This law was enforced by the arrogant Director of National Intelligence, Charlotte Mearing before Sentinel was revived.

Present Day
When Optimus Prime and Ratchet were helping their human allies, they encountered a piece of a machine that was originally part of the Ark. They flew to the dark side of the moon and found the Ark, with both Sentinel Prime, and five Pillars. With the Autobot Matrix of Leadership, Optimus revived Sentinel Prime. Sentinel took the form of a Rosenbauer Fire Engine. When Sentinel Prime and Optimus Prime were talking to each other alone, Optimus thought that since Sentinel Prime was his leader, Sentinel should have the Autobot Matrix of Leadership and lead the Autobots. However, Sentinel said that since he knows nothing about this planet, Optimus should keep the Matrix, teach him about the Planet, and continue being the leader of the Autobots.

Betraying the Autobots
The Decepticon sub-group trio, the Dreads (Hatchet, Crowbar & Crankcase) chased after Sentinel Prime. Bumblebee, Dino, Ironhide, and Sideswipe guarded Sentinel allowing him to escape wherein Bumblebee & Dino killed Hatchet while Ironhide and Sideswipe kill off Crankcase & Crowbar. After the chase scene ended Sentinel revealed his intention, claiming that the Autobots shall realize that Sentinel was not actually going to help the Autobots win the war, but instead turn against them and explained he made a deal with Megatron. In the process he murdered Ironhide with his Cosmic Rust Gun, and wiped out NEST, with only a few human survivors.

The Invasion and leading the Decepticons
With the help of Megatron, Starscream and other Decepticons, they were able to open a space gate so the Decepticons can invade Earth. He decided to spare Optimus, because he was his apprentice once, and he wanted Optimus to watch the fall of the human race. They first took over Chicago and that if anyone tried to infiltrate they would be killed. The also killed most of the people who lived in Chicago (except of Dylan Gould and Carly). But during the invasion, Sentinel Prime attacked Megatron and told him that he's the true leader. He then took over the Decepticons as their leader. Similar to Optimus Prime, Megatron became betrayed by Sentinel. He bullied Megatron to leave so that Sentinel can gain full command of Decepticons, then soon the entire human race who he plans on enslaving to build Cybertron. Sentinel stayed out of most of the battle relying on the Decepticon warriors to carry out his plans, including Shockwave, Soundwave, Laserbeak, and Starscream.

Transporting Cybertron and Death
Other Decepticons were placed around the world with a few of the Pillars. They were going to be used to open a Space Gate and bring Cybertron into the Earth's atmosphere. After the Red Pillar was deactivated by Optimus, (the Pillar that controls all the other pillars) Sentinel Prime fought all the Autobots and N.E.S.T. with little to no effort. While he was fighting the Autobots, Sentinel Prime told any surviving Decepticons to reactivate the Pillar. Turning the fight Sentinel attempted to retreat, but Optimus managed to catch up with him. Sentinel managed to cut off one of Optimus' arms was about to kill him. At the same time, Carly (Sam Witwicky's new girlfriend) tries to convince Megatron to kill Sentinel Prime. She said that if Sentinel did succeeded in killing Optimus and transported Cybertron, Megatron would be nothing more than Sentinel's b*tch. Convinced, Megatron rushed in, saved Optimus Prime, and stops Sentinel Prime by blasting him with the only weapon powerful enough to penetrate his strong hide and pulverizes him hard, claiming that Earth was his planet to conquer, only to be killed by Optimus Prime. Despite Sentinel begging for his life, Optimus grabbed Megatron's gun and executed Sentinel for betraying the Autobot and human races over his awful obsession with Cybertron therefore stating that he "betrayed himself".

Comparisons to the Original
There is very little similarities from the G1 character and the film character. For instance, the G1 version was a hero. Even the movie characters design is different, but he does resemble another transformers character, Alpha Trion. But one thing is very similar; the characters personality.

Transformers: Animated also had a character named Sentinel Prime. He was an Autobot in command of the Elite Guard, and was also an antagonist towards Optimus Prime, but not completely. Sentinel Prime was shown as an idiotic, selfish and rude leader who unfairly bossed around his cadets Jazz, Jetfire, and Jetstorm who are smarter than him. At the end of the series Optimus and his team captures Megatron and saved the universe leaving Sentinel jealous. However, live-action movie Sentinel Prime was far more evil and more aggressively hated by fans than in Animated. It turns out that the reason Animated Sentinel Prime hated Optimus was for leaving behind Autobot; Elita One on a planet filled with giant spiders who he thought killed Elita. However, Animated Sentinel Prime forgave Optimus for this when realizing Elita One became a Decepticon after becoming infected with spider DNA to abandon the Autobots.

Trivia

 * Sentinel Prime is voiced by Mr. Spock himself; Leonard Nimoy, who also did the voice of Galvatron, in The Transformers: The Movie. Sentinel Prime even spoke, "The needs of the many outweigh the needs of the few", which was spoken by Leonard Nimoy's character Spock from Star Trek.
 * It is said that his face was meant to physically resemble famous actor Sean Connery.
 * He was originally going to be named "Ultra Magnus", a failed Prime from the original Transformers movie and a protagonist in third season on the television show.
 * Sentinel Prime is colored yellowish-orange in the trailer of Dark of the Moon, though he is actually colored red throughtout the movie.
 * In an original draft of Dark of the Moon after Sentinel Prime kills Ironhide, had featured him trying to kill Bumblebee but instead kills Skids who got in the way & then Mudflap after he tried to avenge his twin brother. This is still seen in the comic book & novel adaptations.