Orion now know as Optimus, was a gladiator even from a young age. Before he had gone to the pits to start fighting he was introduced to a bot, Megatronus, to which they quickly became good friends, and Megatronus taught him every thing he knew to help Orion. He was with him from the start always there support Megatons ideas and Megatron was there to support him back. But it got to the point where Optimus had become more heartless, dangerous and violent. Megatron liked knowing Optimus would always be at his side and would die for him. He and Megatron became the first Decepticons and together, they took down the council. Optimus was always at his side becoming very protective of him when the war started, almost like his bodyguard.
(This will be almost nothing like the actual story)