All marosapiens have the ability to shift from their humanoid form into a hulking form of their animal type, but these transformations demand constant nourishment and require a significant amount of training to gain enough control to master the additional three forms: savage, bestial, and natural. Those who can achieve all five forms typically exist within a humanoid form, are able display specific animal characteristics in a savage form, take advantage of both natures in a hybrid bestial form, assume a hulking animal form, or slyly adopt the standard sized natural form of their animal type. Each form has specific advantages and can be achieved with, and are detailed within, the Therianthropy proficiency.
Created to be a focus around which the canimaro could gather to better coordinate their attacks on the hivryn, the ursimaro are also powerful enough to stand up against the kreytin without a need for assistance. During their development, the initial species of bear lacked the intensity of the canimaro and ruthlessness of the felimaro, and this easygoing nature did not change with each subsequent species selected. It was soon discovered, however, that once provided with a clear threat, their aggression would turn murderous, after which their placid personality would return.