Onyx Prime is the first Transformer with a Beast Mode (thus, the ancestor of the Predacons) and one of the Thirteen. He is not known to have wielded any weapons, but possessed the Triptych Mask as his artifact.
He was among the Thirteen created by Primus to battle and win against Unicron and seeing the activation of the Well of Allsparks. Unfortunately, during the War of the Primes he was fatally injured, and chose to enter the Well so that the proximity of Primus' spark would sustain his existence. Badly wounded as he was, he was carried into the Well by Optimus Prime, who sought to be reborn as a lesser Cybertronian, and with his friend Micronus Prime accompanying him. He would subsequently employ his Triptych Mask to give varied form to the Cybertronians who emerged from the well, including the original Predaking and the other Predacons. It is unknown what became of him later, though curiously new Predacons ceased to emerge from the Well following the Great Cataclysm.
Onyx has something of an "Alpha" mentality, and enjoyed the advantage that his strange abilities sometimes gave him over the other Primes. Despite this, he is unique in being the only member of the Thirteen who enjoyed a friendship with all the others, even the temperamental Megatronus.
According to some screenshots, Onyx is very similar in appearance to that of a winged centaur, which could be his beast mode, along with the added feature of a bat-like head.
- It is revealed in Transformers: The Covenant of Primus that Beast Prime's name is Onyx.
- IDW Comics featured a version of Onyx Prime who was more similar in personality and role to Prime Predaking.
|The Thirteen Original Primes|
| Prima | Vector | Alpha Trion | Solus | Micronus | Alchemist | Nexus | Onyx | Amalgamous | Quintus | Liege Maximo | Megatronus/The Fallen | Thirteen (Optimus Prime/Orion Pax)
|Sentinel Zeta Prime|
|Autobots | Decepticons | Primus | Unicron | Prime | Well of Allsparks | Cybertron|