Kyoto, Japan- The home of Hamoto Yoshi 20 years ago
A woman walks in behind her distracted husband, her name is Tang Shen, she stands at the door and asks, "So this is what you do with your free time." Yoshi chuckles, "Look, I've trained Splinter to mimic my movements. He's a brilliant little rat." She smiled and walked into the other room.
On a roof across the street a man sits watching Yoshi through a window, he is Oroku Saki. It had been years since he'd had to do this kind of thing. He knew Yoshi would have spotted any of his minions long before they'd gathered anything valuable. As he watched he heard someone approach,"The Foot are not allowed in Kyoto."
Saki turned to face him,"The Hand does not order me." The man went for his sword but before he could grab it a shuriken stabbed into his head and he dropped like a stone. Saki then looked back to the apartment but Yoshi was no where to be seen. Saki looked and saw Yoshi on the roof across from him look right into his eyes. The 2 had once been the best of friends, practically brothers but that all ended when Tang Shen had chosen Yoshi. Since then Yoshi left the Foot as Saki took it over turning it from honorable warriors into little more that a criminal organization. Yoshi was now the last remnant of the old clan.
Before Saki could do anything more of the Hand showed up. He left quickly, Yoshi realized he and his wife were no longer safe here.
New York city 17 years ago
Yoshi arrived home to see his door had been kicked open, he rushed in to see Saki along with several of his men standing over the bloody body of his wife. Enraged he charged for Saki but one of them jumped in the way. Yoshi shattered the man's jaw as the rest rushed him. He fought them bravely but they over powered him and held him down as Saki delivered the killing blow. After they left his pet rat came up to Yoshi nudging his master with his nose. After awhile Splinter wandered out the door and wandered off into the city.
3 days later Hell's Kitchen
Matt Murdock is walking home from the pet store with his 4 new turtles. He stopped at a corner waiting for the traffic light as an old blind man walked past him. Matt saw a large truck barreling towards the old man causing Matt to drop his tank full of turtles on the ground as he ran to push the man out of the way. The truck driver swerved to avoid hitting the boy causing a canister of hazardous waist off the back of the truck. The chemical splashed in Matt's eyes blinding him as the rest washed the turtles into a sewer grate and some landed on Splinter the rat who just happened to be sitting right under the grate. For reasons that weren't quite clear to Splinter at the time he gathered the baby turtles and took them back to the burrow he'd been staying in.
Due to the chemical, with in days Splinter had grown to roughly the height of an average human man while the turtles grew to the size of human infants. Splinter, with his newly increased intelligence knew he would need somethings to take care of the turtles so he went back to his master's home and took everything he thought he would need along with several weapons that Yoshi kept and a walking stick that Yoshi's father had passed down to him. Splinter decided that he would train himself in ninjitsu like his master and once the turtles were capable of taking care of themselves he would seek revenge for his master.