The Masters: As a Race they are known as "Chou." They appear to be reptiles of many different colors, reproduce like mammals, males have crests, females have tentacle tendrils. Gem growths on fore head, arms/fists, and chest region to tell you how old they are.
They can reproduce with other races. (Known as Halfings, no Hobbits in Umbraverse, Dwarfs and Elfs yes, but not Hobbits.)
In the beginning they too co existed with super humanity, and the demonic dinosaurs. When Demon Dinosaurs introduced Destruction Magic, it was the Chou who actually saved the day in splitting relaity into 12 halves. They ruled their own plane in good terms.
The Convergent in which all realites merged was by their hand as well. Despite the fact they are called bad guys by commoners for ruling, the Chou, are pretty damn benevolent. Kept lesser races save from the Titanspawn and literally demons from Hell. But when the lesser races revolted, they went full on dumb evil mode.
Notes:
Technology; They are masters are super tech. Many, many things exist due to them.
Magics:
Reality Spheres; 10 Spheres that govern reality. They taught this to their loyal minions, the Numerical Monks. Who ended up back stabbing them.
Pillars of Heaven: 9 Concepts that hold universes together. Went to the Fate Spinners, who did not betray the Masters.
Infintity; Infinite Stone based magic, baby! Chou kept this to themselves only. And only the strongest Chou can use this.
What is up with them now?: Given the plot. In Umbra Legacy they have lost control of the world. Some still rule lands/castles. Others wander the Earth, using their skills to make livings. Some even accepted by lesser monsters as nobility. humans and the "good' beings treat them as crap and beat them up. Though some Chou do serve them willingly, mostly the ones who are really young and ignorant.
The Overlord, the strongest is dead. But, the Four Top Officials are still alive and plotting their own designs. (The Vizier, The Architect, The Commander, and the Law Bringer.)
Next:
Magic, Supernatural, and Sci Fi. In a blender.