Zack Fair is not dead.
At least not in the way his buddy Cloud believes. It was all just a mind trick, another sick experiment conducted by Prof. Hojo to see if Cloud would be able to defeat Sephiroth burdened with the guilt of his friend's death. It all happened during Cloud's capture at Nibelheim. The twisted, mad scientist implanted an alternate reality into Cloud's memory, deceiving him into believing that Zack died to save his life.
So, if Zack wasn't dead, what happened to him? It's all a bit complicated, but in short, he never fully forgave himself for killing his mentor and friend Angeal. He also feared that a similar fate might result with Cloud if they stayed friends. And with the death of his girlfriend Aerith, Zack unwillingly decided to leave the elite Shinra Soldier group and become a Renegade, searching for the remains of Jenova himself, in hopes of absorbing her powers in an effort to permanently kill Sephiroth and avenge Aerith. But first he had to take a trip back to Nibelheim and behead a certain mad doctor with the Buster.

Wanted to show him a little bit older, reveal his dark side, and the Slaine head was a close match - like a wolf with cold black hair. The base is WWE, with resculpted pants and the boots are from Sigma6. Sculpted most of the details and made the Buster sword from clamshell plastic/apoxie/4 leaf clover.
Certainly hope they do bring back this character. Somehow, they usually always do!
Thanks for hittin' this and taking the time.