Sub-Zero was not one but TWO Ninja's...from China ....however that works. The first one was epic until Scorpion melted his face while the second one was EPIC...until he became a robot were he became... *head explodes from sheer awesome*.
The Elder Sub-Zero
Sub-Zero the elder was walking round one day when he met Scorpion who hates teddies and rejected some chick so Sub-Zero killed him. Later Shang Tsung asked him to fight in one of those bothersome tournaments where he met Scorpion again and had his face melted off.
The younger, EPIC, one
So the last Sub-Zero's brother was off doing something epic when he heard that his big brother had died so he became Sub-Zero. So he fought with Scorpion and kicked his ass and proved to everyone everywhere that he was EPIC. So epic that he was offered to join the Undefeatables but refused because he was THAT EPIC! Seriously, he said no to the Undefeatables! The he met his undead brother Noob Saibot, who was upset because he couldn't be Sub-Zero again.
The Robot Sub-Zero
One night, when Sub-Zero was sleeping,
some bastards his friends gave him to Dr. Robotnik who knew that Sub-Zero had only scratched the surface of epicness. So he turned him into a robot and thus Sub-Zero became a robot. Everything was epic until the battle of Armageddon where Robot Sub-Zero killed Scorpion, who had killed Noob Saibot, but was then killed by somebody.