Metal is rare in that part of the world, but volcanic cliffs made of obsidian sharper provide weapons sharper than steel. Iron and steel rust quickly in the endless mists, and few would want to wear thick armour in the relentless, sticky heat.
When the natives do wear armour, they wear plate made from a local stone that they call 'calima', or 'the protector'. In its natural state, the stone is similar to sandstone and easily carved into plates. Shaman then paint, glaze and then fire the stone. When they are finished, it becomes strong and lightweight enough to be worn as armour.
These suits are considered holy to the local tribes and outsides wearing them are usually subdued with powerful blow-darts tipped in the secretions of the sparkle sloth. The unfortunate captives are then turned over a feared sect of Cannibal Priests; their bodies to be devoured piece by piece until only their heads remain. These are used shrunken fetishes of the Cannibal Priests and as the terrible stories say that they retain the memories of their past lives.