There isn't really specifics. The idea is more or less anything goes. Essentially following disaster on the surface, some left the planet and colonised other planets/asteroids, some hid underground. So mutations/ changes may or may not have happened (depending on what you want your character's background to be more specifically).
There's also scope for animal/human hybrids caused by forced adaptation to the changes. I've deliberately kept details vague to allow more people to be creative and come up with ideas of their own.
ok so I have a better understanding what race would like be descendants of
The world can do. They may not be called Chinese, but since it's essentially earth millennia in the future, there would be descendants of all current races, in some form or another. And martial arts would exist, in some form or another.
I'm interested in joining your rp the kairos but I don't know if they have Chinese people or have martial art in the future