Disclaimer: Not mine.
Shadows
He hadn't expected the shadows he found. During his last scan, Bumblebee had found several shadows marring the surface of his Spark. They didn't seem to be doing anything directly, none of his systems seemed affected, but there was un undeniable sense of something wrong about them. He could determine at least three distinct shadows. One was faded, one was small, and the other was rather large. He could not determine their origin, and it worried him.
He took his concerns to Ratchet, certain the medical officer would know what was going on.
Bumblebee didn't expect the heavy sigh Ratchet released, or that Ratchet would simply gesture him into a seat, rather than whisking him onto a medical platform.
"There's nothing wrong with you, Bumblebee, except that I expected you to be in here before this. Those shadows will be there a while, and there's nothing that will remove them but time."
"But... What are they?"
"Shadows of the Sparks that fell by your hand."
"I've never seen them before, though."
"You're a scout, Bumblebee. That kept you out of the fighting, for the most part. I don't think you've ever had to deliberately make sure someone's Spark was extinguished, in order to accomplish your missions. Incapacitate them, offline them, dismember them how you like, you didn't kill them. These last few years on Earth, however, you've been a key member of our fighting force, Bumblebee. You've taken down Brawl, Ravage, and Rampage, just to name a few."
"Brawl was two years ago! Surely I would have noticed something..."
Ratchet was shaking his head. "One shadow, faint and shifting, probably wasn't enough to trigger an error code. Scans might have taken a bit longer, as the discrepancy was noted, but that's it. Nothing telling you to do a deeper scan."
Bumblebee was silent, processing the knowledge that the Sparks of his foes, some of the most ruthless Decepticons, had left their mark on his own. Sudden fear lit within him, and he threw his head up in alarm, his optics locking on Ratchet.
The medic was quick to answer his unspoken terror. "They can't affect you, Bumblebee. Not really. They can't interfere in your systems at all. It's just a shadow, a spectre of their previous existence."
Bumblebee relaxed, believing Ratchet, and ran a few scans to doublecheck. Now that he knew what the shadows were, he could detect and identify the affect they were having on him. It was just a simple dimming of his spirits, made all the worse by knowledge of what they were.
He imagined being Optimus, or Ironhide, who surely had many more shadows upon their Sparks.
"I never knew." He said, looking back up at Ratchet, who had an undeniably sad look upon his metallic features.
"No one told me."
"It's a sad thing, Bumblebee. We didn't want you to know. We didn't want you to have to know. You're the youngest Autobot, the last youngling we've got. We'd hoped your Spark would remain bright and unshadowed."
Ratchet didn't have to express his regret at their collective failure to protect Bumblebee. It was clear on his face. They couldn't deny the scout the right to fight, especially after he'd been captured, and had faced numerous cruelties at the hands of both Decepticons and humans. But all the same, the loss of the last unshadowed Spark among their number cut deeply.