Those who take up the Oath of the Death Knight were once paladins, either of a great order or acting alone, bound to a sacred Oath that guided their life until their death. After either moments or years, these paladins were brought back through vile and perverted magics, typically by powerful necromancers or by a Lich, they now hang in a state between life and death. Forced to live in this tormented state, these paladins now roam the world either trying to live the life they previously took for granted or embracing their status as a member of the undead army, abandoning the world of the living.

TENETS OF THE DEATH KNIGHT

Typically, the tenets of a Death Knight often stem from good intentions, however the vile sorcery used to resurrect them tends to warp their mind and the typical ideals of "justice", "law" and "chivalry" have often abandoned them.

Evil Must be Destroyed. As a mortal ripped from a peaceful rest, you know all too well the consequences of allowing evils to exist. You must destroy those who would corrupt the world, no matter your personal feelings.

Prove your Allegiance. As a monstrosity to most living souls, you must strive to prove you belong in society, be that through noble actions or great deeds.

Instil Hope. As a creature who feels melancholy and anguish so easily, you must work that much harder to spread the light of hope to those who need it most.

Variant Tenets of the Death Knight

The tenets above assume a Good aligned Oath of the Death Knight paladin, if you are evil or neutral-aligned, you may wish to alter these according to your personal goals. For example:

Crush the Living. As a soldier of the undead, you must seek to destroy living creatures who oppose you.

Oath of the Death Knight Spells

You gain oath spells at the paladin levels listed.

Paladin Level	Spells
3rd	Armor of Agathys, Hex
5th	Hold Person, Misty Step
9th	Animate Dead, Vampiric Touch
13th	Banishment, Shadow of Moil
17th	Cone of Cold, Danse Macabre

 

Oath of the Death Knight Spells

Please note that due to the way the D&D Beyond has their homebrew subclass set up, I've set the spell selection as an option instead of automatically giving them to you, this is due to some of the spells being XGtE and PHB. This means that during the Character Creation process, you have to go through and manually select the spells. This does however give you the freedom to change the oath spells if you don't own the required source books.

Runeforged Weapon

At 3rd level when you take this oath, you learn how to Runeforge your weapons, carving runes of power into them. You carve one rune over the course of 1 hour, which can be done during a short rest. The weapon must be within your reach throughout the carving process, at the conclusion of which you touch the weapon and form a magical bond.

Once you have Runeforged a weapon, you can’t be disarmed of that weapon unless you are incapacitated. If it is on the same plane of existence, you can summon that weapon as a bonus action on your turn, causing it to teleport instantly to your hand. Additionally, when you use your Divine Smite class feature, you can spend one rune to change the damage type of that Divine smite to either Cold or Necrotic damage. Once spent, a rune cannot be used again until the next dawn when it recharges.

You can only Runeforge one weapon at a time and can carve a number of runes on the weapon equal to your Proficiency bonus, but can only carve 1 rune per 1 hour spent. 

Channel Divinity

An Oath of the Death Knight paladin of 3rd level or higher gains the following two Channel Divinity options.

Enslave Undead. As an action, you can target one undead creature you can see within 30 feet of you. The target must make a Wisdom saving throw. On a failed save, the target must obey your commands for the next 24 hours, or until you use this Channel Divinity option again. An undead creature whose challenge rating is equal to or greater than your class level is immune to this effect.

Chains of Ice. As an action, you can cause sharp chains if ice to surround creatures within range. Each creature of your choice within 30 feet must make a Dexterity saving throw. On a failed save, the target is restrained for 1 minute. A creature restrained by this ability can repeat the saving throw at the end of each of their turns.

Aura of Death and Decay

Starting at 7th level, you constantly emit a deadly presence while you're not incapacitated. Whenever a hostile creature within 10 feet of you takes damage, the wound is amplified as your dark energy seeps into their body, inflicting Necrotic damage equal to your Charisma modifier (minimum of 1).

At 18th level, the range of this aura increases to 30 feet.

Voracious Strike

At 15th level, whenever you hit an enemy with a melee weapon attack, regain hit points equal to half of the weapon damage dealt.

Lich King

At 20th level, you can assume the ultimate form of a Death Knight as ice surrounds the area around you. Using your action you undergo a transformation to become the a living embodiment of death itself. You gain the following benefits for one minute:

• You gain resistance to all damage.
• You emanate the aura of a remorseless winter storm in a 30-foot radius. The first time any enemy creature enters the aura or starts its turn there during a battle, the creature takes Cold damage equal 4d10 + your Charisma Modifier. Additionally, the creature must make a Constitution saving throw or become Paralyzed for one minute as ice encases their body.

After activating the aura, you can’t do so again until you finish a long rest.