A/N: Season 3 character death speculation. Ficlet.
One more lost soul to raise your flag
The sky is a landfill
It happened very quickly.
Starscream barely had time to react before the blade went through him. Cockpit shattered, cables severed, energon releasing in a spray before spilling down his frame and down the Prime's arm. Optimus stared ahead as the aerial's claws gripped and slipped on him. Distorted tones sounded as his intake filled with energon, trailing bright and blue from gasping mouthplate.
Starscream lifted his helm, frame in a tremor, plates clattering. The Prime met his gaze. Red optics flashed, wide, confused and in pain. From his field came a pulse of loyalty and hatred in a constant grapple and the kind of mourning that would never leave any Cybertronian. On the outer rims, the Autobot detected long festering insecurity, a dangerous obsession, and most apparent of all, fear.
Optimus closed a gentle hand on the Decepticon's shoulder. Starscream's expression was a clear question. The Prime simply nodded to him, seeing no need for words.
There was no choice. The fate of the planet was at stake. Allowing Starscream to continue functioning was no longer an option. He shuttered his optics slowly.
A hard twist of the blade and all was quiet.
The Prime pulled his weapon from cooling metal and guided the frame down, keeping his gaze away out of respect.
The blade retracted as he stood to face the looming fortress and the coming storm.