The Envoy of Malice is the servant and overseer of the Malice King.
The players first see the Envoy in Sprite Forest and every boss dungeons except the dungeons that are in the Malice King's castle from then on. There, he offers to buff the player that is talking to him for a small price that increases with each dungeon. In The Keep, a black skeleton with a sidequest mentions how the Envoy may be the one who put a monster known as The Abomination to frighten everyone else in the castle.
Some of the Envoy's attacks include teleporting and firing multiple dark balls which can potentially kill players even with high HP if all of them hit. Some others include an attack that homes in the players' location and attacks with a random element that causes a status effect, firing ultrasound waves that confuses any players hit by them, and at times, firing thousands of dark balls in a certain pattern.
Dodging skills are especially needed when fighting the Envoy. A good strategy is to constantly move around while attacking a few times in order to avoid being hit.