Lairon is a stocky, armored Pokémon with four short legs. Its body is dark gray, and its eyes are sky blue. Its back is covered with segments of iron armor, each with a high ridge and round dark holes on the sides. The sides of its lower jaw have several flat protrusions, and two teeth are visible in its mouth. There are two-pronged metal bands on its legs. The upper band is gray and the lower is silver.
Lairon smashes its steely body against others when battling over territory, and shows off its strength with the size of sparks it creates by ramming into rocks. Close inspection of Lairon has revealed scratches and dents left on the armor from its conflicts. It drinks nutritious mineral spring water and feeds on iron contained in rocks. However it has gotten into conflict with humans over these territories in the past. It builds its nest on mountains where iron ore is buried, which results in it clashing with humans that are iron mining.
In Mashing Makuhita, Rono, Sapphire's Aron, evolved into a Lairon before her challenge with Brawly in the Dewford Gym. Although he was her highest-level Pokémon, he failed to beat his Hariyama, but was put into good use against Matt, beating his Pokémon and injuring him badly enough that he was not taken to the Seafloor Cavern sometime later. He evolved into an Aggron on Mirage Island as a result of the training Sapphire underwent alongside Ruby.
Lairon tempers its steel body by drinking highly nutritious mineral springwater until it is bloated. This Pokémon makes its nest close to springs of delicious water.
Lairon feeds on iron contained in rocks and water. It makes its nest on mountains where iron ore is buried. As a result, the Pokémon often clashes with humans mining the iron ore.
When two Lairon meet in the wild, they fight for territory by bashing into each other with their steel bodies. The sound of their collision carries for miles.
Lairon tempers its steel body by drinking highly nutritious mineral springwater until it is bloated. This Pokémon makes its nest close to springs of delicious water.
Lairon feeds on iron contained in rocks and water. It makes its nest on mountains where iron ore is buried. As a result, the Pokémon often clashes with humans mining the iron ore.
Lairon may be based on the Bulgasari, a monster that eats iron in Korean legend. Its draconic appearance was most likely inspired by how it appears in the film adaptation of the legend.