The kleptarthir replaced its ancestor, the armored trapinfilter. It evolved in the warm waters of Clayren Coast, near to the water surface, where the food is abundant. It is very similar to its ancestor, but now the segmented shell is articulated when the creature is young, becoming hard and almost rigid while the creature grows, giving a final shape to the body. They live in colonies and, due to its proximity, even when the food is plentiful, they can steal food from others placing their armored tentacles into the mouth of the nearest kleptarthirs. When full, the tentacles will retract into the shell. Kleptartirs keep spawning huge clouds of spores in the summer, maximizing the chances of their offspring survive. Due to its successful evolution, the kleptarthir replaced its ancestor on Clayren Coast.