If you have not read the Demons page, we suggest you go back and do it, or else you will be greatly confused.
The Xarkrains were the strongest race of Demons, and it's descendants are no exception.
The Xarkrains created some of the strongest races in the history of Demons, and the Xenophan was one of them. The Xenophans were half-breeds created by Xarkrains mating with Humans. While the name "half-breed" may imply that they are weaker, they are not. The first Xenophans were exiled with the Humans, where they learned the secrets of the human mind, psyche, and magic. When they were finally allowed to return to Demon society, they learned the secrets of the Demons, which gave them the option of applying Demon power to Human knowledge; allowing them to cripple Humans in ways never seen before. They also were able to do the same to Demons using the opposite setup. They possessed knowledge that no other Demon or Human could ever comprehend, which made them a nightmare for both races. When this was recognized by Demon society, most of them were killed out of fear, which is why so few remain, and why those who do remain are in hiding.
The Xalerans were by far the strongest descendants of the Xarkrains. It is not known how they originated, but it is known that Retrace was the first. The Xalerans were not alive at all; in fact they possessed a rare trait called a magnetic soul. A being with a magnetic soul could rebuild their body from whatever lies around them, should they die. This ability corrupted Retrace, and he sought to share the corruption with the world. He began to kill Xenophans and turn them into Xalerans. When the supply ran low; however, he receded to a place known as "The End of the World', where he established the Void. From that point on, Xalerans became the most feared species of Demon to ever walk Ashara. Afterwards, the Xaleran became a species of the Void. They are found nowhere else in the X Universe, yet somehow; oddly, their numbers continue to grow.