The Three Classes
Many people have sought to group and classify the creatures that roam across the face of Sena. The most common system divides them into three broad types: Beast, Phenomenon, and Myth.
Beast class creatures are those that resemble and behave like actual animals. They may look similar to normal species, or a jumble of different features, but they all act like normal animals (or rarely plants or fungi) in terms of feeding, reproducing, etc. Beast class creatures are often subdivided based on their resemblance or lack thereof to regular animals. This is the largest class and the one whose members most people are familiar with.
Phenomenon class creatures are a diverse lot, and some debate exists over where the Beast class ends and this class begins. What is generally agreed upon is that the Phenomenon class encompasses those creatures that do not conform to basic biology as regular animals do. Many do not rely on food, or reproduce in unusual ways. For all their unusual traits, however, most Phenomenon creatures still resemble living things of some kind - mostly animals, though a few plants and fungi exist with the usual muddied classifications.
The rarest of all creatures are those that belong inside the Myth class. The name is slightly misleading as many of these creatures have been seen and can be considered to exist, but in terms of describing their power or elusiveness, it is very apt. Most verified Myth creatures are immensely powerful beings that keep their distance from humanity, often acting as guardians of certain places. They have rarely if ever been seen in groups, and it is thought that they are unique beings whose very biology is entirely unlike that of other living things.