Megatron's best mech
G1
Orion Pax, Otimus Prime's, well, first incarnation, wasn't the cute, slightly naive dockworker we thought him to be.
In truth, he didn't just admire the flying mechs of the Decepticon army, he was their spy, completely dedicated to the cause and telling them when to attack the docks and where to strike.
That he was caught in the attack and almost killed, was an unfortunate accident that Megatron still regrets. He such hopes for the young dockworker.
a) But now, vorns later, Orion Pax' memories are returning and Optimus Prime is suddendly torn between leading the Autobots and helping the cause he really believes in.
b) Optimus Prime knew the truth all along and helped the Decepticons without his own mechs noticing. He's working as a spy and saboteur, keeping Megatron informed about any important step of the army, until the last remains of the senate are finally found and slaughtered.
c) Alpha Trion was a Decepticon, too. He chose Orion Pax deliberatedly to be the new Prime.
d) One day, after going through some old files, some Autobot/Decepticon comes across some holoimages or securtiy videos showing Orion Pax either in the company of Megatron or at some other places that were attacked by the Decepticons at the beginning of the war. And he was always there just before the attacks happened. He becomes suspicious but how to tell the devoted Autobot army that their Commander works for the enemy?
e) What else you can think of.