Sentinel Prime
Transformers character
Sentinel Prime as he appears in Transformers One
First appearance	The Transformers
Created by	Simon Furman
Voiced by	Jack Angel, Leonard Nimoy, Jon Hamm, others
In-universe information
Affiliation	Autobots (allied with Decepticons in some continuities)

Sentinel Prime (Japanese: センチネルプライム) is a character in the Transformers franchise. Generally depicted as an Autobot leader, Sentinel Prime has served as either a supporting character or antagonist in Transformers media.

Sentinel Prime was created by writer Simon Furman for the Transformers comic series published by Marvel Comics. He appears in a flashback in Transformers #150 and is shown to be the Autobot leader that preceded Optimus Prime and gave him the Matrix of Leadership.^[a] He was unnamed in Transformers #150, but his name was later established retroactively.^[2] Furman reused Sentinel Prime for the comic series The War Within published by Dreamwave Productions. In this comic, Sentinel Prime is killed by Megatron, and his death triggers the ascension of Optimus Prime to Autobot leader.^[2] Sentinel Prime was used again by writer Eric Holmes for the four-issue comic series Megatron Origin published by IDW Publishing. This comic depicts the origins of Megatron as a miner-turned-revolutionary on Cybertron, which is depicted as a deeply corrupt society led by Sentinel Prime.^[2] Sentinel Prime also appears in the 1980s cartoon, in which he is voiced by Jack Angel.^[3]

Sentinel Prime is depicted in Transformers: Animated as an Autobot rival to Optimus Prime. He is not a villain in the series, but is an arrogant military officer that makes life worse for his allies.^[2] The character returns in Transformers: Dark of the Moon in which he is voiced by Leonard Nimoy. In the film, Sentinel Prime was once a mentor to Optimus Prime, but abandoned his ideals during the Cybertron civil war. He comes to a secret agreement with Megatron to conquer Earth and use its resources to rebuild Cybertron.^[2] Sentinel and Megatron are ultimately both killed by Optimus Prime by the end of the film.^[4]

Sentinel Prime's most notable appearance is in the film Transformers One, in which he serves as the main villain. In the film, Sentinel Prime is a former servant of the thirteen Primes, the original leaders of Cybertron. He grew envious of their power and allied with an invading race called the Quintessons to kill them. After killing the Primes, he takes over the planet's capital, Iacon City, by claiming that he defeated the Quintessons. He keeps the population enslaved as miners so that he can pay debt to the Quintessons. He also creates the practice of removing the transformation cogs from the populace so that they are unable to transform.^[2] When the miner D-16 learns the truth about Sentinel Prime, who he once considered to be a hero, he becomes angry and resentful. The film culminates with D-16 killing Sentinel Prime before taking the name Megatron. Megatron's former ally, Orion Pax, gains the Matrix of Leadership and is named Optimus Prime. This backstory marks the beginning of the Cybertron civil war between the Autobots, lead by Optimus Prime, and the Decepticons, lead by Megatron.^[5] This version of Sentinel Prime is voiced by Jon Hamm.^[3][6]