1. They switched worlds 20 years ago 2. After YS death, YS we got to know ended up in the void. 3. YS we didn't know returned from the game world to the real world - because that's where he belongs 4. YS we got to know followed the sound of the watch and found his way back to JL 5. JL has already regressed so when YS found his way back, he couldn't remember anything
Conclusion: everyone is where they are supposed to be. Our YS just simply lost his memories
1. They switched worlds 20 years ago
2. After YS death, YS we got to know ended up in the void.
3. YS we didn't know returned from the game world to the real world - because that's where he belongs
4. YS we got to know followed the sound of the watch and found his way back to JL
5. JL has already regressed so when YS found his way back, he couldn't remember anything
Conclusion: everyone is where they are supposed to be. Our YS just simply lost his memories