Legend has it that all the Oozes originated as fragments of the Demon Lord Jublex, while that is probably up to the lore of the individual Dungeon Master, it is obvious that they are a created, not an evolved creature.

Orcs are hulking brutes. Very High Strength, Very High Constitution, Above Average Dexterity, Very Low Intelligence. They wear hide armor and use great axes in melee.

The Oni are fearsome bogeymen that haunt the nightmares of children and adults alike. While the question remains: which came first, the Oni or the Fear? The simple fact is that the Oni are now very real and always hungry.

Naga view themselves as the inheritors of their ancient creators, claiming the property, especially the magical items and spell-books that were once possessed by their former masters and creators as their own.

The Naga are an intelligent spell-casting race of serpents that usually lair in areas that contain ancient ruins. The Naga are a created race that was developed by a humanoid race that has been long forgotten by history. It is suspected that the ruins they guard are the former cities and places utilized or sacred to their ancient masters.

As one of the monsters of classic Greek myth, you would expect the Minotaur to be a real challenge, and that any battle with one would be an epic challenge that would leave behind an epic tale.

In order to run a challenging encounter against a Medusa, you must fill in the blanks regarding the former life and the former abilities. Imagine a woman with all the powers of a Medusa, that also had the abilities of a character class such as Bard, Rogue, Warlock, Wizard, or many others. Multi-class options are completely possible.