Sleeping Pods

The Sleeping Pods is what keeps the real Zantou as prisoner and is why the thirteen clones were created and created Dark Water, when Zantou was trapped, Usagi used a whitch named Naminé to make Master Splinter to forget Zantou until he was able to free Zantou.

​16 Years Later
Sixteen years later when The Dark Water Arc occured, the turtles and allies found the memory pods with the real Zantou and soon when all thirteen of the clones were destroyed, Zantou was finally free and reunited with Splinter.