He was still there. Big Mama… She didn’t get rid of him.

The Shredder. He’s still alive and now stronger than ever…

Technically, what had happened was Cassandra, a foot soldier took the ring, controlled the Shredder into attacking the turtles, April, Splinter, Draxum and Big Mama, Draxum took Big Mama’s mystic orb, blah blah blah…

Draxum casted some ritual, sending the turtles to Splinter’s memories to find some sort of weapon or whatever the hell in some Twilight Realm.? And they brought back a woman called Karai, apparently she was Splinter’s great, great, great… At least 11x more great grandma.

But, like the idiot you are, you don’t know that cause you were sleeping like a baby in your bedroom. You woke up to the sound of them getting Karai out of the Twilight Realm.