This is D&D - when you take an 8 hour nap that massive axe blow to your head magically heals completely. There are things that can be done. Sometimes. And sometimes the character is gone. The player, however, does not die. There is that nice little "restart" button you can push to restart the game. Sort of.
That is a long way of saying - you are always welcome in the game and if Thaoran does go meet his father in the long dark night, you can always make a new character.