Both belong to Transformers. Well, let me put it this way. At the beginning, there were two extremely powerful beings, one called Yuanshi Tianzun and the other called the universe emperor. Both of them belong to the existence of God and the concept of the universe. Then they confronted each other. The universe emperor aside, Cybertron (yes, that planet) became the back of the original Buddha, and Transformers later appeared in Cybertron. At the same time of uniting with the Pentecostal, the Pentecostal went to Cybertron and lied that he was the creator and oppressed the Transformers. Megatron led the Decepticons to resist. Actually, to be honest, Megatron is really on the side of Transformers. He is the only one who can save the existence of Transformers. Optimus Prime is a friend of mankind at best, and a traitor at worst. Megatron would have died long ago if the author hadn't kept giving him an aura of mental retardation. Then Optimus Prime used to be a librarian in Cybertron. After Megatron's death, the Decepticons declined, because no leader could coexist with domineering and wisdom like him. He doesn't want to kill Optimus Prime and Autobots, because in his eyes, these are his people, and he exists as a leader. That's it.