Death knight

A death knight is an undead warrior created by a powerful being. Usually they were living humanoids who were evil in life.

Appearance
Death knights typically appear as skeletal warriors clad in plate armor and, in place of their eyes, malevolent lights burn.

The death knight who fought alongside Vecna was not quite goliath-sized, but thick and massive. He was clad in jagged, dark metal armor, and his longsword emanated a dark energy.

Abilities

 * Multiattack: The death knight can make three attacks with its weapon.
 * Hellfire Orb: Once a day, the death knight can hurl a crackling sphere of darkness that explodes at a point it can see, dealing fire and necrotic damage (half damage with a successful Dexterity saving throw).
 * Spellcasting: The death knight can cast the following paladin spells:
 * 4th level: banishment

Known death knights

 * Vox Machina faced a death knight who served Vecna on more than one occasion. Matthew Mercer later revealed this death knight to be an undead servant of Vecna who many centuries vigilantly watched over and kept hidden Vecna's labs in Wildemount, which erned him a reward. As it grew closer to Vecna's ascension, they were elevated to death knight status and became one of the great warriors of Vecna's. This death knight offered Delilah Briarwood a way to save her husband.
 * Pentrakath is a death knight who lives in a cave in the Dreemoth Ravine.

and
Arkhan claimed that his party was attacked weeks earlier by the Remnants, led by the death knight and Delilah Briarwood, followed up by Vecna himself. The death knight incinerated the elf ranger Vander, who Arkhan thought of as a brother, and cut the still-beating heart out of their goliath companion. When Arkhan and Vox Machina approached the top of Entropis, the death knight faced them, and Arkhan decided to take on the death knight alone (with the benefit of haste), saying he would hold the death knight off, and he urged Vox Machina to go straight for Vecna. Deep into the battle with Vecna, they saw that Arkhan had emerged from the fight heavily wounded, but he held the death knight's helmet as a trophy.