I saw a couple self-customs done by some other Sigma 6 fans and knew I had to do one of myself.  Needless to say, since I am the Mysterious Stranger, my custom is masked.  But its all explained in the bio so read on...

Base Figure: Snake-Eyes V.1 body, Cobra Commander head
Paint: flat gray, black sharpie
Accessories: Long Range coat, knife, and keytag, Ninja Armor Snake-Eyes leg armor, Duke v.1 glasses and grenade, Snake-Eyes v.1 night vision goggles, 1/6 scale rifles

I wanted to convey a sense of mystery and intrigue with this custom and the CC head did just that.  The fact that the blue eyes match my own eye color was just a bonus.  I wanted a more cutting edge look for the Sigma suit so I modified the NASE leg armor and removed the blades.  Rit dying the coat black, using a sharpie on the back of the Duke glasses to "smoke" the lenses, painting the accent color gray (to go with the black ops bio) and adding the weapons really made this figure exactly what I wanted.  The night ops goggles and key tag just give it a little more dimension I think.  I'm proud of how this turned out.

Code Name: "Mysterious Stranger"
Real Name: unknown
Covert Operations

Primary Military Specialty: Covert Operations
Secondary Military Specialty: Counterintelligence

Very little is known about the operative referred to as the "Mysterious Stranger".  It is believed that he is a former member of the CIA and NSA and currently works for the Department of Defense under the infamous "black budget" program.  He has been spotted during several highly volatile Sigma 6 operations, assisting in unforeseen ways then disappearing once his mission is accomplished.  He has access to the latest in combat weaponry and gear and wears a modified Sigma suit, presumably a prototype.  The "Mysterious Stranger" carries a special key card around his neck on the same chain as what appears to be a Sigma 6 dog tag.  At this time it is unknown what the key card unlocks.  His motives and loyalties are sometimes unclear and his actions are sometimes contradictory to the objectives of the Sigma 6 team but in the end the outcome is always to the liking of the brass.  Even more enigmatic than Snake-Eyes, the "Mysterious Stranger" is a wildcard and definitely warrants further investigation though previous attempts to delve into his past have been met with resistance from the highest levels. 

General Hawk:  "Whatever his ultimate agenda may be, as long as he's on our side we'll take all the help we can get in our fight against Cobra."