Jon Bon Jovi took the task of writing a soundtrack for Young Guns II extremely literally. The lyrics of the songs on his Blaze of Glory album more or less exactly follow the plot of the movie.
The first-person character singing "Blaze of Glory," then, is meant to be Billy the Kid...or at least Billy the Kid, as played by Emilio Estevez in Young Guns. As Bon Jovi described him, "Billy was an interesting character. He was coldhearted and he loved the celebrity and he couldn't sing. So, he found celebrity, all right, in a gun [...] He was 21 years old and just a little left of normal. You know, he'd wake up and shoot you for a cup of coffee. Not the kind of guy that I want to hang out with." (Source)
Estevez played Billy as a kind of demented, fun-loving sociopath. One uncharitable reviewer absolutely ripped his performance as "the idiotically grinning Emilio Estevez [playing] Billy the Kid, who slowly accumulates a gang of Brat Pack buddies and fashions them into a group of male models with six-guns" (source).
Ouch.
Bon Jovi's version of the character seems to have a bit more gravitas. No hint of idiotic grinning, at least, comes through in the lyrics. There's more than a bit of melodrama, though, and in that the song is very much in character with the movie. Bon Jovi's Billy doesn't have much time for moral introspection. He knows he's done bad things, he knows justice is hunting him down, but he carries no regrets. He's ready to die and wants only to do it "like a man, staring down a bullet, let me make my final stand." In the end, the song offers a halfway decent (spoiler alert) plot summary of the movie.
What's more questionable is whether or not Bon Jovi's (or Estevez's) romanticized conception of Billy the Kid fits the actual historical figure. Billy the Kid was a real human being. He had a whole bunch of names—Henry McCarty, Henry Antrim, William H. Bonney, Billy Bonney—which hinted at the fact that he grew up in a broken family. As Bon Jovi sang, he was "no one's son." His father either died or abandoned his mother when he was just a small child. By the time he was a teenager, young Billy had become a small-time thief in the New Mexico Territory. He was arrested for the first time in 1875.
For stealing cheese. Something we can uh, kind of relate to.
Less than two years later, at the age of 16, he killed a man for the first time, shooting to death a blacksmith named "Windy" Cahill who had been bullying him. Billy was a thin and weakly looking boy. Later that year, on the run from the law for the Cahill shooting, Billy got mixed up in the so-called Lincoln County War, a prolonged conflict between rival New Mexico cattle ranchers. During the course of the war, Billy fought at different times on both sides, and at different times became both a deputized lawman and a wanted outlaw.
The war lasted for two years, with partisans on both sides dying in all kinds of nasty ways. Billy the Kid narrowly avoided being killed on several occasions and he also was involved in several murders. The exact number of his victims remains unclear, although it was almost certainly far lower than the 21 killings—one for each year of his life—later attributed to him in legend. Most historians think the actual number was about four.
However many people he actually murdered, Billy the Kid started to become a minor celebrity in the New Mexico press, and acquired his famous nickname, during the course of the Lincoln County War. The war ended in 1878. Billy spent the rest of his life running from the law, being captured, and escaping from jail. In 1881, Billy's run came to an end when Lincoln County Sheriff Pat Garrett caught up with him and shot him in the dark. The real Billy the Kid never got a chance to take that final stand. His last words before being blasted in the night were reportedly "¿Quién es? ¿Quién es?"—Spanish for "Who's there?" (Source)
After his death, the legend of Billy the Kid only grew and grew. Pat Garrett himself cashed in on his killing by publishing the book The Authentic Life of Billy the Kid in 1882. Since then, Billy the Kid has appeared in fictionalized form in dozens of books and movies. He's been played on screen by Roy Rogers, Paul Newman, Kris Kristofferson, and Val Kilmer, along with Emilio Estevez, of course. He's been hunted down by John Wayne and romanced by Jane Russell. He's headlined songs written by not only Jon Bon Jovi, but also by Bob Dylan, Rambling Jack Eliot and Pete Seeger, Aaron Copland, and Ry Cooder. Billy the Kid has, in short, become an American folktale.
But what about the real person, that teenage boy who found himself mixed up in all kinds of trouble and didn't live to see his 21st birthday? In a sense, the size of Billy's legend hides the fact that we really don't know all that much about the actual human being. Why did he take to a life of crime? Did he feel remorse for the things he did? Did he see himself as a hero or a villain? We don't really know.
Only one photographic image of William H. Bonney is known to exist. In it, the young gunman holds a rifle in his hand. But otherwise he hardly looks menacing. He's skinny and baby-faced and even looks a little bit goofy in his clothes. If it weren't for the gun, his closest resemblance might be Scarecrow in The Wizard of Oz. He's got an enigmatic half-smile on his face. What's he thinking? Is he a stoic outlaw standing there, facing down a bullet, ready to take that final stand? Or is he just a kid scared out of his mind?