Great keepers are bonus dungeonmonsters that have appeared in several Dragon Quest series remakes, before becoming regular enemies with the eleventh game. They are living statues made out of solid gold, but unlike the gold golems they are not hindered by the frailty of the metal.
They might literally have hearts of gold, but they're not overly accommodating of unwelcome guests, turning away would-be trespassers from Zenithia before they can even get a foot in the door