It is an experimental GAARD program for the creation of enhanced soldiers more powerful than average
The Super-Soldier Serum is a formula to create super soldiers. But the name is a misnomer, as the Super Soldier creation actually consists of various processes. Subjects that are considered to have been enhanced to their “Peak-Potential” are noted to be Sarge Hawk, Riff, Thick, Scorch, Shrap and Hoover. Variations of the Super-Soldier Serum have been developed over the years which induced greater-mutations that peak Plastic Soldiers capabilities, but also created monsters by mistake.
So far, it would appear that Sergeant Hawk is the “perfect Army Man”. But some variants come with strange side-effects that may also include mental & behavior deficiencies, like the rest of the Bravo Company Commandos: Thick, Shrap, Hoover, Scorch and even Riff in a less grade.
Some time later the Tan Army created their own Super Soldier clones, copies of Sgt. Hawk and the rest of the Bravo Company Commandos, with exception of Hoover.
Sarge Hawk & Co. were the first Super Soldiers, considered “SS1” (Super Soldiers 1). A few moths later, Super Soldiers 2 (SS2) could begin to be produced. These were still upgraded common soldiers, but also began to be produced from scratch. Although inferior than SS1.
Some time after the production of SS2 started, the Super Soldier molds were stolen by Lord Malice, and were made available to “the highest bidder” and most armies paid the plastic necessary to obtain their own Bravo Commandos copies, since these were still superior to the SS2.
Years later, with the rest of the armies in the great alliance, everyone shared their particular research on the subject and managed to create multiple and more varied types of Super Soldiers. After SS4 and SS5 they practically lost count of Super Soldier numbered versions, being an irrelevant and unnecessary system of classification, because of the different and diverse ramifications that left the standard system.
Rumors of stolen technology
In declassified Tan Army files, made public during the creation of the Army Men Alliance of Nations, it was revealed that the technology and knowledge for Super Soldiers was stolen from the Gray Army, specifically from the Gray Empire, which was defeated in the Great World War.
The Grays possessed no such records, as their archives were burned at the end of that war. When the Green Nation was contacted about the issue, they declined to comment.
Behind the scenes:
Intelligence division eyes only:
Classifications SS1, SS2, etc. They are an attempt to get people interested in them as evolutions of Saiyan from Dragon Ball or Pokemon, achieving a perpetual renewal and redesign of characters in the future, leaving some as they are, like Sarge Hawk, something like how Pokemon fans want them to be. Pikachu forever be Pikachu.