The old world:
So the old world is basically something like a world underground that most people aren't aware of exists. The people that know it exists are mostly old fae that had went there 500 years ago due to earthquakes and monster's starting to affect Twisted Wonderland trying to find a way to help and stop Twisted Wonderland from being affected. This didn't go all according to plan since the destruction of khaenri'ah was still going on and many fae were killed on accident. So they quickly went back to Twisted Wonderland and sealed the entrance to tevyat so that no one will get hurt. The seven didn't just wanna let this information go to waste so they planned to send some strong mages to get some information on tevyat. When they arrived they had an interesting journey not as eventful as the travelers but still rather dangerous. The dangers mostly came from the Fatui wanting to get hold of some fae to conduct experiment to advance their delusions.

How Yuu(Xiao) got to Twisted Wonderland:
When he was out fighting off demons the karmic dept overwhelmed him and managed to gain the upper hand over Yuu. Yuu not wanting to endanger someone ran away before it was too late to fight off the karmic dept anymore. During the right he didn't realize that they're heading towards where a lot of Adepti abodes lay. Behind all of the Abodes is an entrance to a cave wich has a mirror leading to Twisted Wonderland. Yuu who was still fighting off the karmic dept damaged the mirror wich lead to a kind of magic explosion sending Yuu to Twisted Wonderland.

Yuu's(Xiao) problem with sacrificing himself:
Ever since he came to Twisted Wonderland he felt like his purpose in life has vanished and that his existence doesn't have a real meaning and matter anymore. Because of this he almost always when someone close or not is in danger puts his own life in danger so that they can survive. Wich really tire's his friend's out a lot.


I put more effort into this than I do for my P.E. classes