Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2055480.
Edit 4/7/2017 : I was missing two parts. I just added them. They are parts 15 and 16. Thanks BADDOG01 for pointing that out.
After making the Lord Starkiller helmet I had several requests to make a Sith Stalker helmet without the back piece.
I designed this using the pepakura model as a reference.
From Wookieepedia:
Sith Stalker Armor was a type of armor that was cybernetically grafted to the wearer, covering the entire body save the arms. Featuring design details resembling those found on Mandalorian and Ubese armor, Sith Stalker Armor presented a foreboding and grisly countenance. Historically, this type of armor was favored by vicious Sith assassins who were highly feared within the ranks of both the Sith and the Jedi.