2012 TMNT But Its One-sided Demolition Crew (Shredded and Splintered)
So what if. Instead of Saki being obsessed with Tang Shen, he was actually in love with Yoshi. And goes that night to take him away from the clan and his arranged marriage and all that nonsense.
Yoshi is all, "We're brothers dude, not cool." And Saki's, "Nah it's fine bro, I'm adopted." Yoshi like, "No seriously, no homo."
And so they fight, and Shen gets knocked out/dies (Somehow.) and starts a fire when she does.
Yoshi fights Saki off, knocking him out; then runs off taking Miwa outside to safety, then runs back in to get Saki and Shen. He drags Saki out the front door and then goes back in to get Shen, having to fight the blaze to get to her now, extremely dead body. (Rip Shen)
Saki wakes, and hears Miwa crying outback running around the house to save her, just seconds before Yoshi drags Shen's body outfront where he was.
The house collapses just as Saki finds Miwa, and believing his brother is dead and Miwa is all that's left of him, Saki spirits the baby off into the night.
He later finds out Yoshi survived the blaze, buried Shen and then disappeared, and so his long search begins.
Skip ahead 15 years and Saki hears rumors of some "Mutant Ninja Turtles" in America who have a very foot clan-esque style, and he's immediately intrigued. (And desperate for any lead at this point.)
He finds out Yoshi got mutated into a giant fancy rat, and adopted four turtle tots. (Cause of course he freaking did, just make our lives more complicated why don't you Yosh…)
And so then the whole series is Saki trying to capture and woo, and unmutate Yoshi, and the turtle tots just being like "Hell no you are not dating our father, you monster."