Order of the Death Knight

A hero... that's what you once were. You stood boldly against the Shadow and purchased another dawn for the world... with your life. But the evil you fought is not so easily banished; the victory you claimed, not so easily held. For now, the specter of death looms over the world yet again and it has found new champions to bring about its final reign. Knights of darkness, wielding runes of death and destruction, bound by the will of the Lich Queen. This is the hour of their ascension! This is the hour of your dark rebirth...

Death knights are the former champions of the Scourge. They fortify their bodies and drain life energy itself with the power of blood, sharpen their blades and strike powerfully with the power of frost, and raise the dead while striking with the unholy fervor granted by undeath. They are engines of destruction chosen by the Undead Scourge to serve the almighty will of the Lich who raised them. Sometimes a death knight is raised by forces mysterious as well, for a purpose unknown to them.

 

Death knights can feel positive emotions for a brief time and rarely. Bad emotions like remorse and pity they feel deeply. Their memories are often gone or clouded, and they take on new names based on their traits or appearance, should they forget their own. Those who knew them can still recognize them behind their cold eyes, which let off a sort of otherworldly light.

Runecrafting

When you choose this archetype at 3rd level, you learn to craft runes that you can inlay into your blade. Crafting a rune requires you to have any profession that can craft items, as well as the correct tools for that profession. Inlaying a rune into your weapon requires a ritual, done on desecrated ground over the course of one hour, and is only active if you use it. You can have a total of three weapons that have runes inlayed in this way, and each weapon can only have one type of rune on it at a time. Each rune grants the weapon a special property. If the weapon is mundane, it becomes magical.

Frost: Your weapon attacks with this weapon also slow the creature's movement speed by ten feet until the start of your next turn

Unholy: Your weapon attacks apply a disease to the target called a Festering Wound. A creature can only have a maximum amount of these wounds equal to your proficiency bonus. Whenever you roll a 20 to hit a creature with a weapon attack, one festering wound bursts (is expended), dealing damage equal to a roll of your hemocraft die (is not doubled by the critical damage). If a creature has a festering wound and they would be healed for an amount of hit points, a wound bursts, and the healing is reduced by the same amount.

Blood: Once per turn, when you hit a creature with a weapon attack, as long as that creature is not a construct or undead you drain their life force, healing for a roll of your hemocraft die .

Hemocraft Modifier: Intelligence

Your Hemocraft modifier Becomes Intelligence instead of Wisdom.

Hemocraft Modifier: Wisdom

Your Hemocraft modifier becomes Wisdom instead of intelligence.

Lichborne

Also at third level, you learn to control the undead state your body is in, though it is still prone to decay. You do not need to eat, sleep or breathe, and effects cannot put you to sleep. While on Hallowed ground, you have vulnerability to radiant damage, replacing your immunity or resistance to radiant. You gain proficiency with heavy armor. 

Veteran of Forgotten Wars

At third level, your body is bolstered from both the energies which mimic life within you, as well as a history of battles it's weathered to die in the first place. This means the further you progress your undeath, the more resilient you become; but mortal techniques weaken you. For each blood hunter level you have, you gain an additional hit die (1d4, rounded to 3) that does contribute to your maximum HP. For each other levels in a class you have, your maximum hit points are reduced by 3.

Death Grip

At 7th level, you learn to fuel your magic in a new way: a death grip. When you take the attack action, you may first target a creature within 60ft of you. Necrotic energy grabs hold of them. Make a grapple check against that creature, contested by a strength saving throw. On a success, the creature is pulled towards you, to a space within 5ft of you (they are not grappled).

At 15th level, when you death grip a target and they fail the saving throw they are considered to be grappled by you, without the need to have an open hand to grab onto them assuming that they are a size you can grapple.

 

Once you use this ability, you cannot use it again for 2 rounds (recharging at the start of your turn).

Antimagic Shell

At 11th level, you twist the necromantic powers that raised you into a shield that protects you from incoming magic. As a bonus action, you roll a hemocraft die and a hit die (expended) in order to conjure a barrier against magic. The barrier has hit points equal to the roll on the hemocraft die times the roll of the hit die and lasts for an amount of hours equal to the roll of your hemocraft die. Whenever you take damage from a magical source or effect, the ward takes the damage instead. If the source is not magical, the ward takes no damage, and you take the full damage. If this damage reduces the ward to 0 hit points, you take any remaining damage. If the ward is at 0, you may spend a minute doing a ritual in order to expend up to 5 hit die, adding the amount expended to the ward's hit points. This ritual automatically fails on hallowed ground.

Once you create an antimagic barrier, you cannot create another one until you complete a long rest. 

Unholy Fervor

Starting at 15th level, your very soul is constructed differently from that of living creatures, making you easily corruptible. Your will not being your own, if a revival spell is cast on you, it does not require your soul to be willing. In addition, a you feel a deep desire to obey a creature that has resurrected you, and you automatically roll a 5 on any saving throw that forces you to obey a command that these creatures cast, such as the suggestion spell.

You have disadvantage on spells that force you to take certain actions, such as the command spell. You are also susceptible to the magic circle spell. You take twice the damage from the geas spell, and that spell's damage can't be ignored.

While you are under the control of a spell like command, suggestion or geas that damages your free will and you would hit zero hit points, the spell ends, and you drop to 1 hit points instead.

In addition, you may ritual cast the spell Summon Greater Steed bound to you. Your minds are linked, causing you to both be considered the same creature for spells that affect the mind, such as command and psychic lance. The greater steed cannot be killed until you are, and can be conscious while at zero hit points. While mounted, you have advantage on attacks with rune weapons, and while moving on your turn when mounted you have bonus armor class equal to half your blood hunter level, rounded down.

 

Rune Mastery

At 18th level, you master use of your runes. While your crimson rite is on a weapon with a rune on it, that weapon gains the following properties, depending on the rune:

Frost: While you have this rune, your body is bolstered by the extreme cold. You are immune to forced movement, the stunned condition, and cold damage. When you use death grip with this rune, it becomes an icy cold grip of the grave. Creatures gripped and grappled by you have their body and bones frozen, similar to petrification, except they are still a creature, they are not incapacitated, are aware of their surroundings, and instead of having resistance to damage, they take 20 additional damage from fire and bludgeoning damage sources. This ends when the grapple ends.

Unholy: When one of your Festering Wounds bursts, the creature affected is plagued until the end of your next turn (this counts as a disease). While plagued, their attacks, checks and saving throws have a penalty to hit equal to a roll of your hemocraft die.

Blood: Once per turn, you may turn one of your attacks into a death strike. When this attack lands, it drains the target. Expend a hit die. That creature loses that many hit die, rolling them and loses that amount of hit points rolled. You gain those lost many hit points.