Optimus

before Megatron's ark optimus prime is the leader of the autobots student Megatron is his best friend.Cybertron hasn't been destroyed yet Sentinel prime is the master of all prime at that time optimus hasn't become a prime yet sentinel prime is also the teacher of the autobots student optimus is his favorite after 200 years optimus prime became a prime because sentinel prime chose him to become a prime Megatron felt betrayed and jealousy his anger caused the war. you're Megatron continue your story and you can change the war neither you want peace and to keep Cybertron alive or start the war and destroy Cybertron. if you chose Megatron's ark (you) that caused the prime's to fight and the autobots team to flee on earth or just become friends your choice