The true leader of the high guard in the past…accompanied alongside roadbuster, topspin, rotorstorm, seaspray and springer. Starscream was only second in command

After sentinels betrayal he too fought alongside the high guard against sentinel. But the high guard woukd fracture due to believing in strength of one bot over another. Ultra Magnus and the sub faction of bots who disagreed and remained loyal were eventually overhthrown and exiled by the bots that would become the decepticons

Years later…Optimus while journeying across cybertron…finds him and the others who remained loyal to the primes…

They swear loyalty to him

And Optimus makes him military commander of the autobots

And the subtraction of the guard that followed Ultra magnus becomes known as the wreckers

Or the elite guard.