The Voided Heart - Sub!Leonardo X Reader

Machigai

Leo kept running on the rooftops, trying his best to ignore the heavy queasiness in his gut. He aimlessly fled far away from the Bronx, his destination being unknown to him. Then a curb tripped him to the ground, scratching his chin. He rubbed the spot where the little scratch was made, and looked at the little bit of blood on his hand. A gasp went into his lungs when he was reminded of the blood on one of her blades.
She killed people...
She murdered... humans!
She killed the ones who raised her...
Out of revenge...

Leo then thought about one of the the most important lessons Master Splinter taught him and his brothers as a child: "Revenge leads to harm of the ones you love."
The acolytes gave her the inhumane power she didn't wish for. And she wanted revenge.
I should have taught her what sensei told me...
I should not have...

His hands shook, then balled into fists. He got up and ran towards another direction. An alley was under him, and he jumped down into it, and went deeper into the ground through the manhole.

He returned to his home, the lair, where he met up with his brothers and human friends. As he was hesitantly walking past the turnstyles, Raph noticed him first.
"Finally you guys are-" He noticed the lack of (Y/N) beside him. "... What did she do to you?"

"N... nothing..." He mumbled, then he held his stomach tight. The others turned to him in concern.

"Leo, you don't look so good..." Donnie told him. "What happened?"

"She... she k..." His palms got clammy, and he covered his mouth as he hyperventilated.

"April, get him the barf bucket, pronto!" Mikey commanded. She nodded and ran to the bathroom, grabbed it and ran back as fast as she could. Leo immediately clutched onto and regurgitated his lunch into it. Splinter immediately came out of the dojo and dashed to his son, while Casey grimaced and went up to the others. When he finally finished after a few more gags, they escorted him to the couch and sat him down.

"My son, what's wrong?" Splinter asked.

"(Y/N)... killed her fake parents." He finally was able to say. The rest were taken aback.

"... Like, murdered, killed?" Mikey asked, and he replied with a nod.

"But they were acolytes, terrible people who slain her real parents!" Raph exclaimed. "Didn't they deserve it?"

"I know they were absolutely ruthless, but..." Leo began to explain. "I-I just never witnessed anyone getting stabbed like that. Actual people, not alien robots. I just couldn't take it..."

"What was her behavior beforehand?" Splinter asked.

"Whenever we fight the Foot, she was just... different." Leo explained. "She didn't joke around or anything usual, and... that look on her eyes... it was the glare of someone on the brink of insanity."

"Yeah, she would have anger outbursts, even worse than Raph's." Mikey added.

"I would get mad about what you said, but it's true." Raph commented. "I once saw her almost shoot Tiger Claw in the head."

"Hmmm... this isn't good at all." Splinter grumbled. "Did she seem like she was intending to murder you too, Leonardo?"

"... I don't think so..." He replied.

"Then we must keep her from those intentions." He told him. "There will be a time when death may affect our family, so we must stay together. (Y/N) is a part of the family too, and we shall do what we can to keep her with us."

"Remember the lesson you told us about vengeance being destructive to everyone?" Donnie asked. "Maybe she just has to understand that lesson..."

"That's what I thought when I was running like a mindless idiot..." Leo grumbled. Splinter gently placed a hand on his shoulder.