The Forsaken (5e Pantheon)
From D&D Wiki
About 550 years ago, a small group of exiles rose, and banded together from various factions. They started recruiting more outcasts, and eventually found a home in an abandoned area of the Underdark. From there, they built a home. However, the original forsaken wanted revenge, and started training the others to fight. They started raiding outposts and using the materials to build a city armor de them. They did not take slaves. Instead, they convinced the slaves of others to join them and rise. They named themselves The Syndicate, and slowly spread through more of the Underdark. As more and more joined, a rumor started spreading that the original forsaken were angels in disguise, sent to help them. The forsaken did not object. They continued to spread, amassing arcane power, until they changed upon the wounded form of Orcus. They pounced on the chance to vanquish him, and managed to succeed. The power of Orcus coursed through them, making them gods. These Forsaken left the earth, leaving an emperor. These 3 individuals now war with each other, blaming everyone else for the fall of The Syndicate.