Like most Cobra soldiers Grim-Viper started his career in the Viper ranks. Stood out because of his arrogance, brutality, loudness and brawling, but also of his toughness. Showed absolutely no mercy in training which resulted in "accidently" killing four other Vipers on different occasions during martial arts and combat practice. Since Vipers remain anonymous during their career, after these incidents he became known by the notorious nickname: the Grim-Viper.

Obviously, he was too raw, savage and barbaric for the regular Cobra ranks. Road Pig heard of Grim-Viper's reputation and quickly recruited him for the Dreadnoks. For Grim-Viper it felt like coming home. He kept his nickname and made himself a scythe to emphasize his ruthlessness.

Got this description from the "New Character Generator":

"Grim-Viper: This arrogant character has a bald head and a face sculpt that makes them look deranged. They're dressed primarily in a strange shade of black and dark gold with faded purple highlights. Figure includes: shotgun, gun, removable helmet, duffle bag and laser pistol. The figure was first available included with the Moray vehicle and later repainted as a convention exclusive."

For the bald head with deranged face I almost immediately came up with Dhalsim. I chose a torso with a raised collar for the arrogant look. Stalker V2's torso is originally used as a jacket, but I selected arms with rolled up sleeves to make it look like a tactical vest.

Because of his name I decided to make a scythe, the Grim Reaper's weapon. Made it completely from scratch using plasticard. Grim-Viper couldn't just carry this thing in his hands in battle all the time so Alpine's backpack came in handy. It holds the scythe perfectly and has a place for the shotgun as well.
Left out the duffle bag and laser pistol from the description, they just didn't make any sense.