Iron giant

The iron giants (鉄の巨人) are an rare subspecies of giants that exist throughout Earth Land, and one of the stronger creatures in existence. It's been said the iron giants are one of the Five Elementals presiding over the of. Embued with superhuman strength, durability that's augmented by their armour made them an difficult foe to challange, even S-Class mages would most likely perish when confronting them. According to reports, their armour is made out of the rare material known as adamantine, and theorized that the iron giants are the creators of the near-indestructible metal.