Gelero (translated Grero in some of the fan translations) is the boss of Chapter 12x: The Axe of Thunder. Roy and his army enter a cave in this chapter which holds the Divine Axe Armads. Moreover, Roy is unaware that Gelero and his group of bandits also know about the axe and are also pursuing it. Gelero's speech is unusual; he speaks in a sort of "dragging" manner, as shown in the quote: "So this is the end of the caaave? Treeaasure... Where are yooouuu... Answer meee..." . His plan of stealing Armads ends in failure with his death.
—Gelero's death quote in The Binding Blade