The Spider-Slayer Mark XXi was designed by Alchemax and backed by J. Jonah Jameson due to the latter's growing distrust of Spider-Man following his blackmailing at The Raft. They were introduced just as the Goblin Nation initiated their takeover of New York City and were rebranded as "Goblin Slayers" once it happened. However, Jameson refused to launch the Slayers until Spider-Man showed up with the express purpose of destroying him during combat. This callous disregard of priorities lead Gloria Grant to quit her position as part of the mayor's staff in protest. When the Slayers were activated, they attacked both Spider-Man and Spider-Man 2099 before the latter was able to regain control. To his shock, he lost control again, now in possession of the Goblins.
Miguel was abandoned by Spider-Man and left to fend for himself, only to be rescued by the recently restored Peter Parker, who destroyed the machines and convinced the future web-slinger of what happened to him. The slayers subversion by the Goblin King caused them to be deployed against the Avengers, Stone used this as an opportunity to sell them to prospective buyers as the slayers were acquainting themselves well against the heroes.
Later on, Tiberius Stone would make an agreement to sell the Spider-Slayers to Jalfaha Dahn, dictator of the Republic of Trans-Sabal. Accompanying Stone, at the request of Liz Allan, Miguel would come face to face against the Scorpion, who led an army of the Spider-Slayers to retrieve Stone, who had been captured by the resistance members led by Mussaret. Using Lyla, Miguel was able to trick the Spider-Slayers into attacking Gargan. After witnessing the atrocities caused by Jalfana and his army, Stone canceled the deal, forcing the dictator to step down, as failure to comply would cause the Slayers to hunt him down.
- Their deactivation phrase is "He was born with laughter on his lips and a sense that the world was mad!," the opening line from the novel Scaramouche.
- 10 appearance(s) of Spider-Slayer Mark XXI
- 3 mention(s) of Spider-Slayer Mark XXI
- 6 image(s) of Spider-Slayer Mark XXI