Fire Soul only appears in MegaMan Battle Network 4: Red Sun. MegaMan acquired the ability during the DenDome tournament after defeating FireMan.EXE. MegaMan.EXE performs Double Soul with FireMan.EXE by sacrificing a Fire-elemental Battle Chip.
- By charging a fire-elemental Battle Chip, the chip becomes a FireArm that extends across the entire row with a damage of 50 + the Battle Chip's power.
- Also, when the Double Soul is activated, some panels are changed to Grass panels (in a + pattern on each side) and MegaMan can recover on Lava panels.
- Charge Shot: Fire Arm (Covers the 3 panels ahead of MegaMan, dealing 50 fire damage)
- Weakness: Fire Soul takes 2x damage from Water attacks.
- Bosses to use against:
- Fire Soul seems to be underused due to general lack of usefulness of its abilities. Players tend to prefer to counter using the WoodyPowder Battle Chip to generate Grass Panels for Fire-based folders, creating an overall 4x damage bonus with both the Grass Panel and Full Synchro effects.
Along with the respective navi, FireSoul is referred to as Torch Soul in the anime. During a battle with PlantMan.EXE, HeatMan is restored to TorchMan who gives MegaMan Fire Soul. MegaMan proceeds to delete PlantMan with it.