WARNING: The following contains spoilers for Amazing Spider-Man #58 by Nick Spencer, Marcelo Ferreira, Wayne Faucher, Morry Hollowell, & VC's Joe Caramagna, on sale now.
Peter Parker's life has been turned inside out ever since Kindred, formerly his best friend Harry Osborn, stepped into the picture to wreak havoc on Peter's wall-crawling alter ego. That torrent of terror and tragedies has extended itself beyond just Spider-Man, though, going so far as to affect his friends, family, and even his rogues gallery. Due to Kindred's actions, one of Peter's worst enemies is free from all of his inner demons and finally able to live a normal life. It's a nice sentiment, but one that isn't meant to last, as those same demons are actively hunting down their host, and failure is not an option.
Kindred wasn't alone in terrorizing Spider-Man. He brought the Sin-Eater into the fold, using the villain to keep Peter and his allies busy elsewhere while Kindred put his grander schemes in motion behind the scenes. With his magic shotgun in hand, Sin-Eater cleansed every hero and villain he could find of their "sins," not to mention their powers, up until he came across one that even he wasn't prepared to wield. Among those who were cleansed was Martin Li, aka Mister Negative. Since being stripped of his powers, Martin has also been freed of his evil alter ego. Now that he's on the run from his own Inner Demons, both literally and figuratively, Martin has turned to the only person he trusts that he knows will also show him some sympathy. Martin has gone to F.E.A.S.T., the charity he founded as a front for Mister Negative's criminal enterprises, that now rests in the capable hands of May Parker.
Martin Li's story begins in New York, where he was bringing a shipload of Chinese immigrants into New York City as part of the Snakehead Gang's human trafficking operation. When the ship crashed, he took the name of one of the dead immigrants, Martin Li. After going to find the rest of his gang, Martin discovered them all killed by Silvermane. The villain brought Martin to the mad doctor Simon Marshall, who experimented on him, as well as Tyrone Jackson and Tandy Bowen, the latter of whom would become Cloak and Dagger respectively as a result of the experiments.
Martin's reaction to the procedures was to form two separate identities residing in the same body, the kind and caring Martin Li, and the cruel and calculating Mister Negative. Mister Negative would eventually free the Inner Demons gang from under Norman Osborn's thumb, and while he trained them as his personal security force, Negative also used his corrupting touch to turn them into his own dark servants. Many of the Inner Demons had already been experimented on by Oscorp, but with Mister Negative's influence and refinement, the gang became a nearly unstoppable force.
Now that Martin is free of Mister Negative, he knows that it's only a matter of time before all of his demons catch up with him, and he couldn't be more right. Not only is his darker half relentlessly seeking to rejoin with him, but the Inner Demons gang are fighting to bring their master's host body back into the fold, having been given carte blanche to do so by Mayor Wilson Fisk. Luckily, Spider-Man is there to fight back against the Inner Demons, the fact that they're so powerful even acting as a sort of catharsis for the hero to violently unleash some of the rage that has built up inside of him.
Marvel's Spider-Man videogame for Playstation made good use of Mister Negative and the Inner Demons during the course of the game to showcase just how powerful these adversaries are, and that reputation isn't one that's solely relegated to video games. As phenomenal as Spider-Man is, there's little hope for Martin Li to escape his pursuers, though maybe there's hope that he can overcome them on his own.