In the celluloid past, the solo avenger was usually a wronged person seeking personal retribution or would be a formidable warrior with a tragic past, who was ready to fight on behalf of those who couldn't. They would usually be a quiet humble character or a loud, larger than life one, but either way, they would show an unshakeable determination, a bulletproof mindset and arrive with a skill set that the ordinary person didn't have.
The prototype for the "One Man Army" can be seen in a few genre of cinema from all around the world. In American and Italian (Spaghetti) Westerns, we were given the fastest gunslinger. In the East (Japan) the quickest and deadliest sword exponents came via the Samurai and then came the fastest hands and feet (from China and Hong Kong) in the early Kung-fu movies. But what made these early lone wolf warriors different to what would become the definitive one man army trope, was their limited range of skills. The gunslinger was usually just that, take away his guns and we would find out how mortal he was after a single physical beating. With the likes of characters such as John Rambo, John Matrix (Commando) Casey Ryback (Under Siege) and Jason Bourne (The Bourne Identity) we were given characters that were trained in special weapons and tactics, counter-intelligence and the piloting of many different types of vehicles. In an angry outburst about not being able to hold a job flippin' burgers John Rambo says "Back there I could fly a gunship, I could drive a tank, I was in charge of million dollar equipment..." as a way of citing how special and unique his skill set is in comparison to the ordinary human being.
First Blood is an adaptation of author David Morrell's 1972 eponymously titled book. In the film we were given an escalating and realistic guerilla warfare scenario that included; hand-to-hand combat, survival techniques, gunmanship and a use of vehicles in special circumstances. And although I love characters like John McClane from the Die Hard series (who could be said to be display the same skill-set), I see those types of one man army films as almost a sub-genre of a sub-genre - Why? Because their "one man army" status doesn't have them really owning the same skill set. Even with a characters like Robert McCall (The Equalizer) and Brian Mills (Taken) who both have military training and who have both worked for the CIA, their army element vs Rambo's is not really for comparison.
After the cinematic creation of John Rambo, a thousand films went on to use the 'ex-special forces' or 'Vietnam Vet' tag as a major indicator that the character you were dealing with could easily bring about havoc. Major plot points and even gentle twists have been written into many stories, to routinely reveal, that the mysterious but adept character taking out all the bad guys was in fact an ex-special forces soldier. Under Siege, Lethal Weapon and On Deadly Ground are just some of the bigger films that used this approach.
All in all, cinema would not be the same without the one man army trope and we are here to salute it.