A family of crustacean creatures, characterized by a thick, highly mineralized chitin exoskeleton.

Several species of crustens exist, with distinct differences in size and the number of appendages. 

In general, crustens will have eight to twelve legs, with two to four pairs of claws. The larger species will have an exoskeleton several canes in diameter, with the maximum being the 12 cane wide Curvull species, native to the trove Tangee.

Crustens have several minor biomagnetic propulsion glands inside their appendages, and while they cannot achieve flight, they have been observed to vault great distances in search for prey.

Crustens have also been observed to “fall into the winds” from the edge of troves and hold each other to cluster into large groups, which will then drift from trove to trove. Because these inter-trovian flights are primarily dependent on the winds and not the crusten’s propulsion glands, such observations lead to the creation of the first aviation route maps.

Flying crusten groups are considered to be a severe aviation danger.