Mouth of Unicron

The Mouth of Unicron<ref>As it is called in the film's screenplay: https://www.indiewire.com/wp-content/uploads/2024/12/TRANSFORMERS-ONE-FSS.pdf</ref><ref>Also, as it is called by artists who worked on One: https://www.instagram.com/geraldartsy/p/DBmy8AtS2cm/?img_index=4</ref>, sometimes called a "cave with teeth", or the Grave of the Primes<ref>Transformers One Sourcebook</ref> is a concealed cave in the mountainside of Cybertron. Its inner chamber was the site of the Primes' final battle against the Quintessons.

Fiction

One film

The Primes were at war with the Quintessons for thousands of cycles. After receiving a message from their aid Sentinel, promising intel about a secret meeting of Quintesson commanders, the Primes agreed to meet Sentinel in the cave. The Primes were quickly ambushed by the Quintessons who descended from above, and were betrayed by Sentinel, who killed Nexus Prime, Megatronus Prime, and Zeta Prime. Sentinel attempted to claim the Matrix of Leadership, but it disappeared in his hands.

Fifty cycles later, Orion Pax, D-16, Elita-1, and B-127 journeyed across Cybertron after discovering an old beacon from the Quintesson war, still broadcasting a set of coordinates located somewhere on the planet's surface. Discovering the "jagged mouth of a concealed cave",<ref>As described in the film's screenplay. https://www.indiewire.com/wp-content/uploads/2024/12/TRANSFORMERS-ONE-FSS.pdf</ref> the cogless miners descended into the cave, where they discovered the fallen bodies of the Primes. Plant life had overgrown over the Primes' bodies, which were broken and scattered about. As D-16 mourned the death of his idol Megatronus Prime, Orion Pax observed that Zeta Prime's body did not carry the Matrix of Leadership. Orion would quickly discover the body of Alpha Trion, whose body was still functional. Orion provided an Energon cube to Alpha Trion, reviving him.

Alpha Trion exposed the truth about Sentinel to the cogless miners, before granting them cogs from his fallen siblings. When Sentinel's forces approached the cave, Alpha Trion provided Orion Pax with the details of Sentinel's betrayal so that all in Iacon City could learn the truth. As the four miners left the cave through a tunnel, Alpha Trion fought Death Trackers before being captured by Airachnid. Trion would later face Sentinel Prime, who would kill the last Prime. One

References

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