What is your BBEG's goal?

Current campaign I'm running has a tripartite BBEG which all inhabit one body.

The original owner of the body is a half-elf whose early life started with the persecution of his half-elven parents who were originally killed (elves are not looked kindly in the setting), and eventually found purpose in his later life helping a young hero become emperor of a divided kingdom as his leading magic advisor. Eventually after said hero ascended to emperor, he began conquest of other lands and an alliance of various states fought against the empire. Said half-elf was in charge of a project utilizing forbidden elven magic to help the empire one-up the enemy with minimal loss of life on their part (basically creating artificial humanoids with no souls to help fight in the empire's war); however, he was outed to the local inquisitor state by a magic rival in the close circle of the emperor and was essentially assassinated (or so it seemed, he got away with his life barely). Said inquisitors brought this up with the emperor, and the rival who leaked the information suggested pinning on the half-elf to take the blame. After gaining back his health although losing precise control of his hands, the half-elf quickly learned that he was blamed for the project; he was devastated at the perceived betrayal of the one who he thought was a close friend. The culmination of this, the difficulty of using magic due to the damage to his hands, and his lifelong exposure to persecution broke him and had him venture a way to avenge the wrongs done to him. This eventually led him to meeting an ancient evil that found a kindred spirit in his intense hate who bestowed upon him a fraction of his aspect and mended his hands. The half-elf also absorbed the soul of a ancient dead elven mage, gaining the mage's powers which were far beyond most modern mages. The half-elf's ultimate goal to is to avenge himself, and destroy the empire he helped create to spite his former friend for the perceived betrayal; however, what he doesn't know is that the ancient being and the elven mage that are now part of him are attempting to use him to their own means...

/r/dndnext Thread