Authors Note: These are heavily influenced by several sources, mostly the original Shattered Glass comics. So, yeah, bye.
Megatron:
Megatron stares in amazement as Vector Sigma slowly comes to life. The key hums slightly in its lock, blue light pulsing through the metal. The floor opens as two rings revolve around a brilliant blue light. In the center of this light, the Matrix glows with a light of its own. It pushes towards Megatron, stopping just out of reach. He stares, humbled, at this mythical relic of bygone days. He reaches out to touch it, but a voice from behind stops him. He turns in time to receive a wicked uppercut to the jaw, sending him flying to the other side of the room. Staring in fascinated horror as Orion Pax forces the Matrix into his own spark, he hears it keen in pain. "Orion, no!" Megatron screams at his former friend. Orion stands, his body still changing as the Matrix's power flows through his veins. "I am no longer Orion Pax. I am now, Optimus Prime!" Megatron staggers to his feet and charges Orion. He turns and flees with the former gladiator hot on his trail. Megatron can feel Cybertron dying beneath his very feet while he pursues Orion to the surface. As he bursts into the open, Orion Pax is nowhere to be seen. Megatron opens his comm. link sighing into it, "Soundwave, I need a bridge. Orion has the Matrix. Cybertron is dying." A swirling ground bridge portal opens in front of him and he steps through.
Megatron watches as his former home darkens. He stands on the bridge of his new ship, the Nemesis. "I will find you Optimus Prime. There is nowhere in this universe you can hide from me. I will revenge the destruction of Cybertron and cleanse the planet of your poison. This I vow, with all my spark."