Iron

Iron serves as a rank-and-file knight within the Purple Smoke Knights, an elite combat group.

He is primarily characterized by a powerful but risky ability that hardens his body by controlling the iron within it.

Iron’s signature power is based on the principle of martensite transformation, a phenomenon in metallurgy where rapid cooling of heated steel increases its hardness.

By heating the iron content within his own body and then instantly cooling it, he can freely adjust the hardness of his flesh, effectively turning parts of his body as hard as steel.

He can harden different regions of his body for offense or defense, such as reinforcing his limbs to strike or shield against attacks.

This makes him a formidable close-combat fighter, as he can weaponize his own body without external armor or weapons.

However, his ability has a critical drawback.

When he hardens the joints in his body, those joints lose mobility and lock up, making it impossible for him to move properly.

Iron’s main weakness comes from the very nature of his hardening ability.

If his joints are hardened, he becomes stiff and nearly immobile, leaving him vulnerable.

Another limitation is that the hardening of his joints is temporarily released when he launches an attack.

This brief window of softness in his joints exposes them to counterattacks if an opponent notices the pattern.

Iron notably fought underground against Takehisa Hinawa and Takigi Oze.

In this confrontation, his opponents carefully observed the timing of his ability.

Takehisa Hinawa and Takigi Oze realized that Iron’s joints lost their hardness the moment he attacked.

Exploiting this critical timing, they accurately shot through his joints while they were no longer hardened.

With his joints damaged and his mobility destroyed, Iron was defeated in that underground battle.

This encounter highlighted both the terrifying power and the fatal vulnerability of his martensitic hardening.

Martensite

This is the name of Iron’s core technique.

By rapidly cooling the heated iron within his body, he induces a martensitic state, dramatically increasing hardness in targeted body parts at will.