Dark Knight

The Dark Knight is a warrior who uses his own Blood to decimate his opponents. Using Blood Clots they create from their very blood to channel darkness Dark Knights are born out of necessity, and not necessarily by desire.

Vehement

At 3rd level you gain proficiency in Intimidation checks. 

Harbinger of Darkness

When this archetype is chosen, you learn how to manipulate life force into techniques called Dark Arts. These techniques are fueled by life force in the form of Blood Clots.

Dark Arts : These sinister techniques are fueled by life force in the form of Blood Clots. Some effects may remain active as long as you have 1 or more Blood Clots. Multiple Dark Arts can be performed in a turn if you have enough Blood Clots unless stated otherwise.

Blood Clots: You have CON Modifier Blood Clots. You regain all Blood Clots on a long rest or spend 2 times your CON mod to restore 1 Blood Clot as a Bonus Action. This damage is done as Necrotic Damage and cannot be reduced by any means. 

Saving Throws : Some Dark Arts require your targets to make a saving throw to resist the Dark Art's effects. The saving throw DC is calculated as follows:

Dark Art Save DC = 8 + your proficiency bonus + your Constitution Modifier

Dark Arts

These simple Dark Arts have marked the beginning of your ominous pilgrimage. These Dark Arts are available at 3rd level.

Black Tendril : Spend a Blood Clot to launch an inky black tendril from the palm of your hand as an action. Make a melee spell attack with your CON modifier as your spellcasting modifier to grapple a creature or object you see within 20 feet of you. You may choose to deal 1d6 of necrotic damage to the creature. As bonus action you may move the creature up to 10 feet or damage the creature as long as the creature is restrained by the tendril. You may release a creature or object as a free action. A willing creature can choose to be pulled by this spell without an attack roll. This Dark Art is treated as a spell but cannot be cast with spell slots. When outside of combat, you may use this Dark Art without consuming a Blood Clot, however it cannot deal damage. 

At Higher Levels. The spell’s damage increases by one die when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).

Blood Ward : Spend a Blood Clot to create a shield of Darkness around yourself or a friendly creature you can see as an Action. The target gains two times your proficiency bonus as Temporary HP. 

Dark Wave : Spend a Blood Clot to release a wave of Darkness in a 15 foot line from your weapon as an Action. Any creature within that line must make a Wisdom saving throw and take 1d8 necrotic damage on a failed save. The damage die increases to a d12 if the creature is below half health. This Dark Art is treated as a spell but cannot be cast with any Spell Slots.

At Higher Levels. The spell’s damage increases by one die when you reach 5th level (2d8 or 2d12), 11th level (3d8 or 3d12), and 17th level (4d8 or 4d12).

Siphoning Edge : When you hit a creature with a weapon attack, you may spend a Blood Clot to restore half the damage dealt as HP. 

Somberance

Starting at 7th level, a hazy aura begins to emit from you in a 10 foot radius. This aura will always manifest itself as long as you have a Blood Clot. When a critical hit is made and the target is within your aura, that target must make a Charisma saving throw. On a failed save the target is frightened of you. As a free action you may hide this aura, you will not receive any effects from this feature and other aura based Dark Arts as long as the Aura is not visible.

Additional Dark Arts

Your travels has expanded your reservoir of darkness. As a result you gain access to these Dark Arts at 10th level. 

Bloodletting : Spend a Blood Clot to cure a status ailment on yourself or another creature. You take your CON modifier times two necrotic damage upon successfully clearing an ailment.

Haunting Shock : When you have at least one Blood Clot your aura releases bolts of dark energy. When an attack on a hostile creature is landed within your aura, they take an extra 1d4 of necrotic damage. 

Souleater : Spend a Blood Clot to coat your hands in a hazy purple Aura. When you land an attack you can choose to roll 2d12. You may add the result to your damage dealt as necrotic damage but you must also take that roll as necrotic damage rounded up. The effects of this Dark Art last as long as you maintain concentration. This Dark Art cannot be used at the same time as Siphoning Edge. Any weapon used while under the effects of this Dark Art is treated as magical.

Sullen Presence : Spend a Blood Clot to modify your aura so that any creature within your aura that you can see gains disadvantage on Charisma checks as a bonus action. This effect lasts 1d6 rounds. 

Additional Dark Arts

Your connection to darkness grows even deeper. These Dark Arts may be used once you reach 15th level.

Calamity Barrier : You gain resistance against psychic, radiant, necrotic, and force damage when you aura is active and you have temporary health. This effect extends to any friendly creature within your aura that has temporary health.

Dark Shift : You can now access a dark void within your aura. You may store items within in this void. You may call items to your open hand as a free action. You can store and retrieve items with this Dark Art only if your aura is active. 

Edge of Darkness : When attacking a creature within your aura, add your CON modifier to the damage roll. This damage is necrotic. 

Veil of Suffering : Spend a Blood Clot to force a creature you can see within 30 feet of you to make a Constitution saving throw as an action. On a failed save, any damage you receive is directed to them. On a successful save, damage is split equally between you both. Odd damage is rounded up. This Dark Art is treated as a spell but cannot be cast with spell slots.

Living Dead

At 18th level, when your HP falls to or below zero, you may choose to spend all of your remaining Blood Clots to stay conscious for that many rounds once a day. You regain use of this feature after a long rest. This feature will not activate against an attack that would have killed you outright. You cannot die while this effect is active.