While Sub-Zero was killed by Scorpion earlier in the series (becoming Noob Saibot), this character has always been available on the roster. Recognised for his ability to freeze enemies (and then proceeding to break their bodies into pieces), this ninja/assassin is mysterious and utilizes the element of ice in battle.
This character ranks on the power list due to his longevity and change; dying yet coming back in a new form and having his younger brother assume the identity of Sub-Zero makes the person a symbol that can’t be destroyed. Much like Batman. Don't start your Jason Todd theories.