This fanfic was written in response to a comment by Minion_Energon_101 about how too few people seek out angst or plotbunnies from the original 1987 cartoon, even though there's plenty of material — especially in the last few seasons, but the potential is definitely there in other seasons as well.

This one takes place right after one of my favorite episodes, "Donatello's Duplicate," in which our favorite mad scientist Turtle clones himself in order to have someone else to do the scut work, only for the clone to immediately turn on him and threaten the whole city.

It's also one of the few episodes in which one of the Turtles actually kills his enemies, and you can clearly see that Leonardo, Michelangelo and Raphael are visibly disturbed by what Donatello did. Hence, this fic.

Also note that I'm including familial relationships in this fic, even though I know there is usually no observed familial relationship in the series. I've never been sure why. Think of it as an AU, if necessary.

"You killed him."

The three words echoed faintly through Donatello's lab, but they carried with them the impact of a thunderclap. He stiffened slightly, setting aside his wrench and looking up from the device he had just finished taking apart. Part of him was dreading what was coming next.

Leonardo was standing in the doorway, looking graver than usual. He was always the most serious of the four Turtles, but now he was staring at Donatello with stern eyes that barely seemed to blink. Even his posture reflected his mood — his legs were set wide apart, as if he were expecting someone to charge at him, and his hands were on his hips.

And perhaps it was just a sense of misplaced guilt, but Donatello thought he heard disapproval in his older brother's voice.

"What?" Donatello said.

"Your clone," Leonardo said. "You killed him."

Donatello inhaled deeply. "Yes, I did."

"And the three other clones as well. You tricked him into just… killing all of them."

"Yes, I did." Donatello looked down at the electronic boards on the table in front of him, without really seeing any of the pieces. He began flicking them around aimlessly, just to give his hands something to do. "Why do you bring it up?"

"I just didn't… I just didn't expect you to do that."

Donatello hadn't expected it either. He hadn't really thought about what he was going to do about the clones until the very last minute, when he had thought up the one thing that could get rid of all of them for good. He had gambled on the clone's ego being swollen enough that he could be taunted into destroying himself and all he had created — and Donatello had won. His clone had been tricked into reversing the cloning machine, which had affected all clones in its vicinity, even ones that it hadn't produced.

The clone had lived just long enough to see the clones of the other three Turtles vanish into thin air, before he himself dissolved into nothingness, screaming in horror. And then the cloned rats swarming through the city had followed suit, leaving the city free of their pestilence.

Donatello had known that he had done the right thing. He knew he had now. But when he had turned back to his brothers, he had seen them all looking at him in alarm. As if he had done something terrible. He had turned his attention to disassembling the cloning machine, just so he wouldn't have to look at them anymore.

He looked up at Leonardo defiantly. "I had to do it, Leonardo. He was going to kill me — and the other clones were going to kill you and Raphael and Michelangelo. It was necessary."

"I'm not saying it wasn't," Leonardo said, coming a little closer, his unblinking eyes still fixed on Donatello's face.

His gaze was making the genius Turtle uncomfortable, so he kept his face turned towards the circuit boards. He still wasn't entirely sure what Leonardo was getting at, but he suspected he wouldn't like it.

"Well, good," Donatello said with a false air of cheerfulness. "So we agree. I did what had to be done."

"Yes, you did," Leonardo said hesitantly, his gaze flickering slightly as he moved opposite Donatello. "I—I wish it hadn't been necessary to kill him — to kill any of them, really — but… you were justified. They were about to murder us all, and it counts as self-defense."

Donatello's fingers gripped the circuit board in front of him, until he worried that it would snap in half. He released it carefully, and instead clasped his fingers tightly around one another.

"So why do I hear a 'but' coming?" he said.

Leonardo sighed. "I didn't come here to lecture you, Donatello."

"Then why are you here?" Donatello said, a hint of hostility creeping into his voice. "Why did you come in here and say 'You killed him' as if I did something wrong, if you think I was justified in killing him?"

"Because you don't seem to be bothered by it!" Leonardo suddenly erupted.

His words hung in the air between them like a thundercloud, too thick to dissipate and too stormy to ignore. Donatello looked away sharply, feeling himself growing tenser and angrier by the minute. On the table, his knuckles were showing white under his deep green skin.

"I don't know what you mean," he said stiffly.

"Yes, you do," Leonardo said. "I don't like that you did it, but I won't say you were wrong. But I am worried that you don't seem upset that you killed a thinking, living being."

"A clone."

"He was still a person. A terrible one, but a person. The same went for the other clones."

Donatello picked up a screwdriver and jabbed it into a knot in the wooden table, as if he were trying to gouge it out. Leonardo recognized what that meant — he was feeling awkward and possibly guilty, but didn't want to show it to anyone else.

"What concerns me," Leonardo continued, "is that you killed someone. For the first time ever. That—that should really leave an impact on someone."

"Well, it didn't," Donatello said stiffly.

A heavy silence fell between them, broken only by the scraping of the screwdriver across the wooden table. Donatello was studying it intently, as if he could end the uncomfortable conversation that way.

"Why?" Leonardo finally said.

"Why what?"

"Why aren't you affected by this?"

Donatello's shoulders stiffened. "Because I have nothing to feel bad about. I don't have any reason to be affected by it, because—"

"I know, I know. You did nothing wrong. But even if you didn't do something wrong, it should feel bad to kill another living creature. You seemed almost… almost relieved when it happened."

"I was relieved." The words came out in a strange, distant voice. "Because it meant he was gone."

Leonardo frowned, drawing back slightly. "You hated him that much? For trying to kill you?"

"No!" Donatello erupted, spinning in his chair. His eyes were burning like a pair of embers behind his purple mask. "I hated him because… because he was everything that I hate about myself."

"He was… what?"

The words flowed out of Donatello like water from a broken dam. "He was arrogant. He was superior, haughty, condescending. He looked down on everyone else for not being as smart as he was, but also wanted them to acknowledge him and tell him what a genius he was. He was cold and cruel and — and he cared about nothing except his own brilliance."

He pressed his hand against his face, and Leonardo saw anguish ripping itself through his eyes. "And the worst part is that… that everything bad about him is inside me as well. I have to fight against those thoughts and feelings every single day, but he — he was all those things out in the open.

"Some part of me wants to look down on others for not being as smart as I am. Or wants to be praised for my intelligence. Or cares about my inventions more than other people. Some parts of me are arrogant and cold and contemptuous. He said… he said things to you guys that I — that I've thought in my worst moments, but never said out loud because I didn't want to hurt you guys. He was only a clone, but he was too much like me…"

He swallowed hard, and raised his head to glare at Leonardo defiantly, with tears sparkling in the corners of his eyes. "You want to know why I wasn't upset when he died? It was because when he died, it felt almost like I had killed the parts of myself that I hate. It wasn't the reason I killed him, but it was… it was almost like being set free, even though I know all those feelings are still inside me." His voice faltered. "And I was… I was ashamed that you guys got to see all that ugliness that I hide from you."

The screwdriver clattered to the floor, fallen from a nerveless hand.

The silence fell between them again, like a velvet curtain dropped over a stage. Donatello's gaze had sunk back to the floor, where it wandered aimlessly as he tried to avoid looking at his brother.

Finally, Leonardo reached out and rested his hand on Donatello's shoulder. "I understand," he said quietly. "But you have to remember that that clone wasn't you. Yes, he was like you in some ways — it was inevitable, since he had all your memories and knowledge. But you make the choice every day to be better than he was, and you have nothing to be ashamed about as long as you keep fighting against your worse impulses."

"I'm glad he's gone," Donatello muttered.

"Come on," Leonardo said. He pulled gently at Donatello's elbow until the inventor rose from his chair. "Michelangelo is making a pizza right now. It should be ready any minute."

Donatello sighed. "Pizza sounds good."