Unlike all other species inhabiting the planet Evo, most monstrous life forms cannot absorb magic passively from the local ecosystem, thus they must either consume living beings or feed from tainted pools of power directly in order to sustain themselves. While not strictly parasites, monsters and demons fit poorly if at all into local ecologies, perhaps in part because their nature appears to be highly malleable compared to animals that have evolved over many thousands of years. By the time that an ecosystem manages to adapt to or fight off a given species of monster, the creatures have often already begun to transform considerably. In addition to being a great deal more aggressive and cruel than most animals, certain monsters can achieve a level of intellect rivaling even human beings, complete with spellcraft and rational thought.
The distinction between monsters and demons comes from the divergent methods by which such creatures hunt for sustenance. Both feed upon Evo’s natural energy, the force known as magic that flows throughout the land and all living creatures dwelling upon it. Monsters are corrupted beings that consume this vital force directly from plants, animals, people, and at times the land itself. Thus, monsters are frequently specialized towards hunting a specific type of prey, although they contribute nothing to the local ecosystem like the land’s natural predators. Demons on the other hand, are a rare subset of monsters that are able to feast directly from the tainted energy residing within monsters and other demons as well. They are apex predators, uniformly deadly and often highly intelligent. Consuming many doses of concentrated corruption tends to make the physical forms of demons a great deal more malleable than those of monsters, allowing them to continue to transform as they become more and more powerful.
Deadly monstrous life forms known as bosses, also referred to as war-class entities, possess incredible power, often sufficient to alter the outcome of a conflict between units on the battlefield. Even lesser bosses generally require a well-prepared party to defeat, as running into one unexpectedly is usually a death sentence for a lone adventurer.