Dread Emperor

The Dread Emperor was one of the first major enemies Vox Machina fought prior to the stream. He was a deviation of the standard Dread Emperor from Dungeons & Dragons. As an NPC, he is played by Matthew Mercer.

Background
The Dread Emperor was a being that existed within his own pocket dimension, which appeared as a giant gothic castle with a large bramble forest surrounding it. He found the company of children pleasing, enjoying their youth and spirit, and as such would go into the Material Plane to scout out for and bring back children to his realm in the guise of a child with black hair and golden eyes. In his true form, he wore gold armor. When the children became too old, he would kill them and put their bodies in the castle basement.

Before the Stream
Vox Machina was tasked with investigating the disappearances of various children throughout Tal'Dorei. Hearing about the suspicious child which would appear a week before each child disappeared, they went off of that as their only lead. Eventually, while celebrating their efforts for saving the city of Emon, they noticed the child talking to Sovereign Uriel Tal'Dorei's son. They attempted to capture the child, but he kidnapped the sovereign's son before they could do anything. However, they managed to find a way into the Dread Emperor's realm.

During the final encounter in the Dread Emperor's library, he was using four children chained to him as human shields to share the damage from the attacks Vox Machina sent at him. In order to defeat him without harming the children, the party tried to free them from him. They were able to save 3 of 4 children as the last child was accidentally killed by Keyleth when she got into a tug-of-war with the Dread Emperor and the pressure on the child's collar broke his/her neck. Despite this, they were able to defeat the Dread Emperor.

Recent Events
The Dread Emperor's pocket dimension remained following his defeat. It was to here that Vox Machina banished Craven Edge after its full power and dangers were revealed.

Aftermath
It is assumed that Vox Machina was able to return the surviving children to the Material Plane where they could be reunited with their families.

Vox Machina briefly reunited with one such child and his mother when encountering a camp of refugees from Westruun after the Chroma Conclave's attacks.

Personality
Little is known about the Dread Emperor other than he enjoyed being around children and their youth. However, when his own life was at stake, he was willing to use those same children as a means of defense, even at the cost of their lives. He also killed the children that got too old, all of this suggesting a very amoral personality.

Abilities
The Dread Emperor's abilities are unknown, although it is clear that he possessed great power.
 * Able to create his own small dimension
 * Polymorph

Notes & References

 * The Obsidian Spire Campaign Wiki: Dread Emperor (Obsidian Spire information and story is not cannon to Critical Role)