Here's how it happened:
* The Quintessons: This race of cosmic criminals, obsessed with creating perfect beings, had a hand in Optimus's creation. They were responsible for the original Matrix of Leadership and the body that would become Optimus.
* The Unicron Seeds: Unicron, the embodiment of chaos, spread his essence across the universe, planting "seeds" that could corrupt beings.
* The Nemesis Matrix: The Quintessons had access to one of these seeds and used it to create a corrupted Matrix, a dark counterpart to the Matrix of Leadership.
* The Corruption: When the Quintessons reanimated Optimus's body, they used this corrupted Matrix, imbuing him with Unicron's essence. This created Nemesis Prime, a twisted, evil mirror image of his original self.
Key Points:
* Nemesis Prime wasn't born, but rather resurrected as a dark reflection of Optimus.
* Unicron's influence played a crucial role in his corruption.
* The Quintessons, through their actions, are ultimately responsible for his existence.
It's important to note that the exact details of Nemesis Prime's creation vary across different Transformers media, but the core elements remain consistent: he is a dark reflection of Optimus Prime, brought about by the combination of Quintesson technology and Unicron's influence.