Onyx Prime is a fictional ancient Autobot Prime in the Transformers mythos, especially associated with Transformers: Prime and related franchise lore. He is portrayed as a powerful primordial figure tied to the earliest history of Cybertron and the lineage of the Primes. As one of the legendary Primes, he serves as a symbol of ancient strength, wisdom, and the deep past of Cybertronian civilization. His role is mainly mythic and historical, shaping the background of the Prime legacy and the struggle between Autobots and Decepticons.