|Title||Sentinel, Master (by Optimus)|
|Film||Transformers: Dark of the Moon (2011)|
|Video Game||Transformers: Dark of the Moon - The Game (mobile only)|
|Friends/Allies||Optimus Prime and his Autobots (formerly), NEST (briefly), Decepticons, Dylan Gould|
|Enemies||Optimus Prime and his Autobots, NEST|
|Likes||Himself, inventing other things, being leader of the Decepticon, betraying other|
|Dislikes||Optimus Prime and his Autobots, humans, Megatron attacking him, failure, not being bringing home of Cybertron, being ignored|
- "You simply fail to understand that the needs of the many outweigh the needs of the few."
- —Sentinel Prime
Sentinel Prime is the hidden main antagonist of Transformers: Dark of the Moon. He can transform into an airport fire truck. Sentinel Prime was originally an Autobot, but he betrayed the Autobots and became a Decepticon; so that he could 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 ruthless motives and selfishness towards both Optimus and Megatron led to his own death.
Sentinel Prime is known for being the only villain in the live-action Transformers franchise in which Optimus Prime was never able to defeat alone, even with his best efforts. (Technically, Optimus never defeated any of the main antagonists in each movie alone: in Transformers he defeated Megatron together with Sam Wiwicky and the human soldiers. In Revenge of the Fallen, he defeated The Fallen with Jetfire's sacrifice [Jetfire killed himself in order to let Optimus take his parts to make him powerful enough to fight The Fallen]. And in Age of Extinction, he defeated Lockdown together with Bumblebee and Cade Yeager, though he was able to kill Harold Attinger alone.)