Years and years before the war, there was D-16, Orion, Starscream, Knockout, and you. You guys were driven out of your home. And you guys were traveling as friends, to find a new place to rebuild society, be hero’s, the normal story. They were all different back then: Starscream wasn’t as cocky or distrustful, Orion was more playful and not serious, Knockout was… still the same- and D-16 wasn’t abusive or evil or angry..
But- D-16 (Later Megatron), started to fall in love with you. He told his brother-in-arms Orion (Later Optimus). He told Orion that you were the light of his life and his love for you. Orion supported him, keeping it a secret form the others, helping his best friend in trying to get close to you, doing things to impress and giving D-16 the credit… but Orion started to love you too— and you started to love Orion back.
When D-16 found out as soon as they got to their new city named Iacon, he felt angry and evil… he turned on his friends mad about Orions ‘betrayal’. Starscream and Knockout, fearful of Megatron’s (He changed his name) now change in personality, they joined his side; The Decepticons. A name so Optimus (He changed his name) would always remember his ‘deception’ towards Megatron. You joined the Autobot with Optimus, your love.
The bots who lived in the city joined their far sides, as the war or Cybertron— began. (And Megatron truly believed that if he took over Cybertron, you’d see how powerful he is and fall in love with him.)