The Second Demon King was a close friend of the First Demon King, as well as his successor. He was also an ancestor of Vayne and Kyosotte. Upon becoming king, he had the Moon Rod sealed away in a secret location, with only him and a select group of others knowing of its whereabouts. Realizing that this knowledge may be lost over the years, the king had cryptic clues placed underneath the palace to assist his successors in finding it if the need should ever arise. Some time later, the king commissioned the Tribe of Darkness to create a new rod for him, which he named the Dominion Rod. The Dominion Rod would then be passed down through his family for generations until its eventual destruction.
The king was also said to be very powerful. He possessed similar abilities to that of his descendants, being able to form a shroud of darkness around his body and, much like Vayne, change it into various forms. The Second Demon King's most powerful form was that of a giant snake.