Because he is Earthrealms savior, and he must stay in Earth in order to protect it. (MK4 timeline)

Funny thing is, if he goes along with Kitana to Edenia, and becomes king, Earth is in danger. There was noone better at the time to protect Earth than Lui Kang.

Because he is Earth's Champion of Mortal Kombat. He must remain on Earth to defend his title.

Course, since he died, I don't know if that's now void...

He rejected her offer cuz he knew this was her way of saying "i'm pregnant"

He's gay.

Exactly what i was gonna say!

Darn Ya beat me to it

I believe it is now void. He died... He is no longer the MK Champion. There is no MK Champion now, but if they were to put Liu's soul back into his body and he would be alive, I wonder if he would be considered as the current champ or not???

Anyways I think if Liu went with Kitana, then Liu may of never died and he would still be considered as MK Champ, and probably would still defend Earthrealm.

Well.... there has only been one champion of MK for the whole series... well actually 2... Goro was current champ back in MK1. But there hasn't been a tournament since MK2. MK3 up to MKA has just been one war after another really. I hope for the new MK that it goes back to being a tournament with many warriors fighting to be MK Champ.

Damn!! They Beat Me to the gay answer . Well it doesn't really matter now, Kitana probably won't want to do the horizontal monster mash.LOL!

cuz' he likes kung lao's butt hole.

No one would be able to reject Kitana.... he's obviously lacking common sense.

Celibacy. Shaolins do not marry.

But Liu Kang violates so many conducts and credo of the xialin, that it is not funny, that is, of course...if we are handling the Order of Light as the very same organization as the real life Shaolin in China.

lmao! Most rational explanation yet.