- Uncle Genju (Only appearance)
- Samurai Robots (Only appearance) (Death)
- Fire Monster (Only appearance) (Death)
Firestar encounters another mutant with powers identical to her own. His name is Sunfire and as the pair develop a relationship he reveals to her that his uncle Genju needs their assistance in igniting his Fusion Reactor; a machine which Sunfire believes will supply energy to the entire world and benefit all of humanity. Unbeknown to Sunfire, his uncle’s true motivation is far more sinister. Genju plans to use the couple's combined powers to release his fire monster, a creature of mass destruction under his control. Iceman meanwhile has misgivings about Firestar becoming emotionally involved with Sunfire due to a bad confrontation he had with him in the past. Spider-Man and Iceman decide to investigate Genju’s company Ichi-Ban Electronics. Robots capture the duo as Sunfire and Firestar, unaware of the true situation, ignite the fusion reactor. The fire monster is released as the couple is drained of their power. Firestar and Sunfire manage to free their friends who help them regain their powers by using the residue energy in the fusion reactor. The four heroes then attempt to stop the monster from destroying the city. Firestar drains a nearby water source and Iceman freezes the water. Spider-Man lures the creature towards them as Firestar and Sunfire melt the ice. The monster is extinguished in a torrent of water. The lovers say an emotional farewell as Sunfire departs to ensure his uncle receives the best possible help.