Sentinel Zeta Prime is an Autobot from the Aligned continuity family.

Believe in the Sign of Zeta.

Sentinel Zeta Prime was originally an officer in the Elite Guard before being named Prime. Under pressure from the various guilds of Cybertron he oversaw the rise of the caste system that came to dominate Cybertronian society, a policy which brought him into conflict with Alpha Trion, and ultimately led to the archivist's self-imposed exile in the Iacon Hall of Records. By the time of the rise of the Decepticon movement, time had robbed him of much of the fire which had made him an effective military leader, and this left him out of touch with the people he claimed to represent.

Fiction

The Covenant of Primus

Born some time before the Age of Wrath, when the Quintessons, the rogue creations of Quintus Prime, colonized Cybertron and enthralled the technologically inferior Cybertronian race, Sentinel Zeta was installed as their puppet ruler, ruling with thirteen subordinates and forming the Elite Guard as a police force. Recognizing his situation for what it was, Sentinel rallied several Cybertronians into an organized resistance against the invaders, managing to drive them off the planet.

Reverse engineering the discarded Quintesson technology, Sentinel used space bridge technology to oversee the foundation of 200 Cybertronian colonies in a Golden Age until the Rust Plague spread across the empire. With no cure to be found, and the disease piggybacking across the space bridges, Sentinel was forced to detonate them all, starting the Age of Rust, an act that Alpha Trion felt had stolen the fire from Sentinel's own spark. Trion later gifted Sentinel with the Badge of Vector Prime which didn't do much to reignite the fire.

At Trion's behest, Sentinel charged the archivist Orion Pax to find the Matrix of Leadership and become the new Prime, an act that sparked the Great War. Dismissive of the threat, Sentinel was taken captive while watching a performance at Altihex Casino. Held prisoner for most of the war, Sentinel was killed after a rescue attempt, Megatron tearing open his chest to claim the key to the Plasma Energy Chamber. The Covenant of Primus

Aligned novels

Though not one of the Thirteen original Transformers, Sentinel Prime ruled Cybertron since near that time. Having already overthrown Cybertron's Quintesson rulers during the Age of Wrath, Sentinel oversaw Cybertron's space bridge expansion to worlds such as Gigantion, Velocitron and the Hub, and the construction of Trypticon Station. But as the space bridges grew less reliable and the Golden Age drew to a close, Sentinel reorganized Cybertron into Guild-run castes, an action Alpha Trion opposed, forcing him to retreat forever into the Hall of Records in Iacon. Sentinel also became reclusive, enforcing the notion he did not care for the lower castes.

When the Kaonian gladiator boss Megatron began preaching against the caste system, Sentinel dispatched the security agents Bumper and Fastback to investigate him. When their identities were exposed, Megatron brutally murdered them—an act for which Sentinel blamed both Megatron and himself. It was while attending a performance by comedian Armorhide at Altihex Casino when Megatron's Decepticons attacked. Sentinel did not try to fight back, and relied on his bodyguards Starscream, Thundercracker and Skywarp for his safety—only to discover they were part of the plot, and they delivered him to Kaon to gain favor with Megatron.

Megatron occasionally desired to take out his anger on Sentinel, but Starscream saw him as a potential bargaining chip—perhaps as a trade in a ransom deal—so they compromised and had the Prime moved to Moon Base One. As the war with the Autobots lulled, Starscream visited Sentinel and offered him a chance to redeem his cowardly behavior at Altihex. As Megatron plotted to take the Plasma energy Chamber beneath the High Council Tower, Starscream released Sentinel and he confronted Megatron below Iacon. Though he was an agile opponent, Megatron literally disarmed Sentinel and cut open his chest, exposing the Code Key of Justice needed to access the Chamber within him. Starscream removed the Key and Blackout was ordered to return Sentinel to Kaon.

Sentinel was chained to a pillar in the Underworld pits that he had despised his whole life. But he was able to send a distress signal which Prowl received, and he, Jazz and Sentinel's replacement Optimus Prime arrived to rescue him. Sentinel said he had overstayed his welcome as Prime and said the High Council made the right decision in appointing Optimus. Before dying, he ordered Optimus to journey to Cybertron's core and purge it of Megatron's Dark Energon. Optimus returned Sentinel's body to Iacon, where it was laid to rest. Exodus

Rage of the Dinobots

After Cybertron was left almost entirely deserted due to the war, Swoop called dibs on living in Sentinel Prime's abandoned palace. Rage of the Dinobots #4

Games

Transformers: War for Cybertron (Xbox 360/PS3/PC)

Voice actor: Troy Baker (English), Sylvain Lemarié (French), Miguel Ángel Montero (Spain-Spanish)

Just watch, Megatron will realize he didn't need Pandora's box after all.

When Megatron launched a raid on Trypticon station, and Starscream joined the Decepticons, Jetfire escaped to warn Autobot leader Zeta Prime that the Decepticons had access to Dark Energon. Zeta Prime sent a large group of Autobot soldiers to guard the Energon bridge that Jetfire knew Starscream and his crew would be reactivating in order to refine an endless supply of Dark Energon for the war effort, ordering that all Decepticons would be shot on sight, but they were unsuccessful. After the Decepticons began manufacturing Dark Energon in mass quantities, Megatron led the attack on the Autobot capitol of Iacon, intending to take the Omega Key, a tool that would allow access to Cybertron's core. Megatron's plan was to pump the powerful Dark Energon into the core in the hopes of reviving the planet and restoring it to what he claimed would be its "former glory". He found the Omega Key's resting place...but it was gone, Zeta Prime having anticipated Megatron's plan and taken it under his personal protection himself. Megatron simply declared that he would take it from Zeta, who appeared several more times via holographs during the missions, warning the Decepticons to turn back before it was too late and Zeta would be forced to execute them.

Megatron's team managed to fight their way to Zeta Prime's chamber in the Iacon Vaults, where he was in control of a mechanism that not only rendered him invincible to all attack, but allowed him to create holographic energon clones of himself and manipulate the ceiling to crush the Decepticons. However, the device had a fatal flaw — it generated tremendous heat, requiring the core to periodically open up in order to cool down, allowing Megatron and his Decepticons to damage it. As Zeta Prime's machine crumbled around him, he was pinned to the floor by the wreckage. He told Megatron to finish it, but instead, the Decepticon leader squeezed his spark casing, forcing Prime to release his grip on the Omega Key. As Megatron gloated in his victory, the "key" started to flash and beep. Zeta Prime laughed, mocking Megatron for heeding the words of his misinformed spies. The device Megatron now held in his hands was not the Omega Key itself, but merely the device that activated the Key. Zeta said that Megatron would only have to wait for the Omega Key to come to him.

Zeta Prime was taken to Megatron's Kaon Prison Complex, but elsewhere on Cybertron, Omega Supreme, guardian of Iacon and, as it turned out, the true Omega Key, was activated with a mission: Destroy Megatron.

After the defeat of Omega Supreme and the corruption of Cybertron's core with Dark Energon, rumours spread through the Autobot camp that Zeta Prime was dead. A young soldier named Optimus was forced to take temporary command of the Autobots and lead the defensive efforts of Iacon. After Starscream was defeated in the Decagon's communications tower, a message, seemingly from Zeta Prime, was played to all Autobot frequencies. Zeta reported his location, and claimed that he had acquired information vital to the Autobot war effort. Ratchet warned that it was an obvious trap, despite the confirmation of his unique ID signature, but Optimus determined that if there was a chance Zeta was still alive, the Autobots must try to rescue him.

"We need a new guy. This guy's kinda...dead."

Allowing themselves to be captured, Optimus, Bumblebee and Sideswipe were imprisoned (and then broke free), only to learn from Megatron himself that he had orchestrated Zeta Prime's message, their capture and their subsequent escape, so that Megatron could talk to Optimus in a situation he controlled. After being captured and escaping again, Optimus' team freed the remaining Autobot prisoners and Air Raid (who had helped orchestrate their first escape), then set off to find their leader. Eventually, Zeta Prime was found, being tortured by Soundwave in his laboratory. After Soundwave was bested by the Autobots, in desperation, the Decepticon drew energy from the injured Zeta's spark itself, mortally wounding him, though Optimus took a final bullet from Soundwave for his erstwhile commander. Optimus promised to bring Zeta home, but with his last breath, the Prime said that while he appreciated the noble sentiment, it was already too late. Zeta Prime, leader of the Autobots, was dead.

Optimus took Zeta's body back to Iacon, presented it before the High Council, and begged them for guidance in these desperate times. The leader of the Council stated that they existed only to choose Primes, and that it was the Primes who led the Autobots. When Optimus responded that there were no Primes left, the Council leader asked if Optimus would still reject his true calling. The Council said that for too long they have watched the Primes fall to greed and pride, but Optimus was one leader whose wisdom and courage inspired and transformed the lives of those around him. Charging him with the mission to remove the infection of Dark Energon from Cybertron's core, the council bestowed leadership of the Autobots onto Optimus, a burden and responsibility he accepted. He was now Optimus Prime, the last Prime. Transformers: War for Cybertron

Transformers: War for Cybertron (DS)

After the Autobots severed the link between the Energon Bridge and Cybertron's core, Zeta Prime ordered Optimus to protect the library while he himself took the Omega Key to a secure location. Little did they know that they were being spied on by Laserbeak, who reported back to the Decepticons. The Decepticons eventually tracked him down to Iacon library where, protected behind a force field, Zeta Prime unleashed defense systems on them. Unfortunately he made the mistake of putting the power sources for the force field outside said force field, and the Decepticons were able to disable it and blast him. Defiant to the last, Prime told Megatron to go scrap himself. To Megatron's surprise, the "Omega Key" turned out to activate the real key — Omega Supreme.

Following Omega Supreme's defeat, Zeta Prime was taken to Kaon Prison. While held there, he attempted to send a distress call to his old friend Optimus. Once the Autobots retook Iacon and got the Data-net back online, he was able to get through and tell them where he was. Optimus and a group of Autobots fought their way into Kaon prison and eventually found their leader on the verge of death. His dying wish was for them to take his body back to the Autobot council. Transformers: War for Cybertron (DS)

Transformers: Fall of Cybertron

Fall of Cybertron

Transformers: Rise of the Dark Spark

Console

When Shockwave and Sharpshot found themselves in an ancient research laboratory, Shockwave discovered a record about the Dark Spark narrated by Zeta Prime can be seen as a hologram narrating it.

Transformers: Rise of the Dark Spark

Notes

• As revealed in the unlocked concept art in the Extras menu of the Transformers: War for Cybertron video game, some early colour schemes for War for Cybertron Zeta Prime resemble that of Generation 1 Sentinel Prime. Also revealed in the concept art is that Zeta Prime's vehicle mode is a Cybertronic car, though he doesn't actually transform in the course of the game.
• Behind-the-scenes material gives the character's name as "Sentinel Prime", which is reflected in both the novelization and comic book adaptation of the game. At some point, the character's name was finalized as "Zeta Prime" in the game itself. When questioned about this discontinuity at BotCon 2010, Hasbro's answer was that the character's full name was "Sentinel Zeta Prime". 2011's Transformers Vault approaches the naming issue by referring to the character as "Cybertron's leader and sentinel, Zeta Prime". The "full name" would be officially used in 2013's The Covenant of Primus, which gives him a design inspired by Animated Sentinel Prime.
• Zeta Prime is a playable character in multiplayer and Escalation mode as part of a DLC pack released on September 7, 2010. He was available for the Xbox 360 and PS3 versions of the game, but not for the PC version. He is a member of the Leader class and transforms into the vehicle mode shown in his concept art. His character model in multiplayer is designated the "Elite Rig".
• In the game, Zeta Prime shares the same character model as the head member of the Autobot High Council.
• In Exodus, Sentinel Prime's belt has the sigil of Vector Prime. However, he doesn't wear a belt in War for Cybertron.
• The dead Prime seen in the Prime episode "Alpha/Omega", whose arm is harvested by Megatron so that he can use the Forge of Solus Prime, is identified as Sentinel Prime by The Art of Prime. The concurrently-published Covenant of Primus identifies him as the Liege Maximo. The dead Prime's arm in Prime is red-colored, which neither Sentinel nor Maximo are.

Foreign names

• Japanese: Zeta Prime (ゼータプライム Zēta Puraimu)
• Russian: Zeta Prime (Зета Прайм Zeta Praym)