The way Ed Boon spoke it looked like we'll find out Who is Sub-Zero in the story mode rather than the comics.

According to the solicitatons Scorpion and Takeda will find themselves in a frozen city in #5, so I guess that #6 could be a huge chance for Bi-Han or Kuai Liang or a totally new Sub-Zero to appear.

Actually we will see Sub-zero in chapter 9 which is the next chapter.

Because Kano will be telling someone about his encounter with Sub-zero.

I'm not in a rush to see Sub-Zero yet, the Kotal Kahn chapters are so badass!

I have a feeling Takeda and Scorpion are going to be seeking out Sub-Zero due to Raiden's shady agenda. The last time we saw Sub-Zero he was marked by one of the Kamidogu so I have no idea what's in store for him.

In due time my friend.