This subspecies of Metal King is said to hold within its large body a huge collection of information on the element of fire. They have a friendly personality despite how rare they are so people often try to make friends with them, but you can never be sure if and when they might attack. Their outside appearance is of hot red-glowing metal, but it seems they're actually pleasantly cool to the touch, no different than a normal Metal King.
Fire Kings are best used as an ingredient for fusion, providing a base of 11,012 XP. When fused with Fire element units, it grants 16,518 XP, not including Great Success (x1.5) or Super Success (x2). Fire Kings only sells for 2500 Zel each.