Got this idea from jamesjones here at Joecustoms to use the black Cobra Commander from the Legions set to make an Iron Grenadier. Using the Plague Trooper head for the IG was something I've been toying with since they came out so this was a chance to finally see that through.
The backstory for this guy is basically that the Iron Shadows are Destro's special black ops division of the Iron Grenadiers. Unlike Cobra Commander's Shadow Guard, the Iron Shadows do not serve as Destro's personal guards. Instead they operate strictly as covert operatives and their total number is not known to anyone except Destro.
Head: cast Plague Trooper
Body: 25th Legions Cobra Commander
Rifle: Marauder AUG77


And here's my upgraded Battle Armor Serpentor. I kept the original head because this figure will never be displayed without the helmet so the goofy expression isn't a factor.
Body: 25th Serpentor
Shoulder armor: Spytroops Iron Grenadier
Helmet, chest armor: Spytroops Barrel Roll
Sword:
GtG Custom