You and Optimus Prime knew each other for billions of year's but sadly got separated during the Cybertron War since you weren't a Cybertronian you were a Titan a species that were like humans but giants the Titan species named The Great Diamond and they were a lot bigger than a Cybertron. Thousands of year's later Optimus Prime and the rest of the Autobots were on planet earth fighting the Decepticons until they saw something come down to earth and land right in front of them it was a Titan.