Iron

Iron is confident in the durability granted by his Ignition Ability and approaches combat directly. He readily explains the principle behind his hardened body to his opponents, comparing the process to the heat treatment used to strengthen metal.

He shows little concern when ordinary attacks fail against him, relying on his hardened body to withstand punishment while closing the distance. His straightforward approach suits the Knights of the Purple Smoke's role as combatants sent to eliminate intruders in the Nether.

Iron is a Third Generation pyrokinetic whose ability exploits the iron within his body. By heating that iron and rapidly cooling it, he changes its structure according to the principle of martensitic transformation. The resulting Martensite technique dramatically increases his body's hardness, giving him durability comparable to hardened steel.

His reinforced body can withstand bullets and allows him to use his physical strength offensively without injuring himself. Iron can smash through structural material with his blows and combine his hardened body with flames for attacks such as Really Hard Fiery Iron Fist. He can progressively increase his durability through techniques identified as Hard Flames and Very Hard Flames.

The ability has an important mechanical limitation. Iron cannot maintain the same extreme hardness throughout his joints while moving freely; fully hardening them would restrict his movement. Consequently, he must soften vulnerable joint areas when attacking or repositioning, creating openings that a sufficiently observant opponent can exploit.

Iron participates in the White-Clad operation against Special Fire Force Companies 2 and 8 when the two brigades conduct a joint investigation of the Nether. Under Ritsu, the Knights of the Purple Smoke attack the separated Fire Soldiers while reanimated Infernals overwhelm the underground complex.

Iron encounters Takehisa Hinawa and Takigi Oze. His hardened body initially renders Hinawa's gunfire ineffective, forcing the Company 8 lieutenant to analyze the physical mechanism behind Iron's seemingly impenetrable defense rather than simply increasing his firepower.

Hinawa realizes that Iron must release the hardening around his joints whenever he moves. Takigi uses his Second Generation ability to interfere with Iron's flames while Hinawa precisely targets the exposed joints, allowing the pair to overcome Iron's otherwise formidable defense.

Ritsu commands the Knights of the Purple Smoke, the White-Clad unit to which Iron belongs during the Nether operation.

Orochi is a fellow Knight of the Purple Smoke deployed during the same operation. Like Iron, she possesses a specialized Third Generation ability designed for direct combat.

Sasori serves alongside Iron as another member of the Knights of the Purple Smoke.

Takehisa Hinawa is Iron's principal opponent in the Nether. Hinawa studies the mechanics of Iron's hardening ability and discovers that his joints become vulnerable when he moves, then exploits those openings with precision gunfire.

Takigi Oze fights alongside Takehisa Hinawa against Iron. His ability to manipulate existing flames helps disrupt Iron's attacks and creates the conditions for Hinawa to target the weak points in Iron's hardened body.