The Blood Knight is a fighter who harnesses the raw power of their own life force to fuel devastating abilities. Drawing from their own blood, they augment their own and their allies strength, and enhance their combat prowess at the cost of their vitality. This discipline is for those who embrace the brutal cost of power, willing to carve, sacrifice, and spill their own blood for the sake of victory.

They strive for victory in such fervor that they go so far as to use their own blood to fuel an ancient and forgotten rite of blood magic. Not a school of magic itself, but an odd mix of transmutation and necromancy - the control over life and the molding of it to suit their needs. Usually Blood Knights are solitary, not beholden to any order or creed. Perhaps they once were, but were driven away by their overzealousness for power.

Blood Magic

At 3rd level, your practice of blood magic grants you blood dice equal to half your Fighter level (rounded up). These dice represent the well of power you can draw from your own life force to fuel your Sanguine Arts and other abilities. When you expend a blood die, you take necrotic damage equal to the number rolled, ignoring resistance and immunity. The blood die is a d4 at 3rd level, and it increases in size as you gain levels in the Fighter class. The blood die becomes a d6 at 7th level, a d8 at 11th level, a d10 at 15th level, and a d12 at 19th level.

Sanguine Arts: Sword & Shield

At 3rd level, you learn two Sanguine Arts: Sanguine Sword and Sanguine Shield. You can expend blood dice to use Sanguine Arts.

Sanguine Sword: You can siphon the life force of your enemies with your strikes. When you make a melee weapon attack, you can expend a blood die and deal additional necrotic damage equal to twice the damage you take from your blood die.

Sanguine Shield: You can call upon the power of your own blood to form a protective barrier. As a bonus action you can roll your blood die and gain temporary hit points equal to twice the damage taken plus your Constitution modifier.

Sanguine Arts: Resist and Rebuke

At 7th level, you gain two additional Sanguine Arts: Crimson Resilience and Crimson Rebuke.

Crimson Resilience: You fortify your body with blood magic. When forced to make a Strength or Constitution check or saving throw, you can use your reaction to expend a blood die and add the result to the total, potentially turning failure into success. You can do so after the roll, but before the result is determined.

Crimson Rebuke: Your blood magic responds to the pain of your wounds, empowering your strength in battle. With your reaction, when you are hit with an attack, you can expend a blood die to make an empowered strike. You have advantage on this attack and deal bonus necrotic damage equal to twice the necrotic damage you take from your blood die.

Bonded by Blood

At 10th level you’ve mastered the flow of blood between living creatures. Once per long rest, as an action, you can touch a willing creature within 5 feet to form a Blood Bond with them for one minute. This bond presents as a thin red incorporeal thread between you and your bondmate. The bond ends if you and the bonded creature are further than 60 feet apart. While bonded, your bondmate receives the following benefits:

• If the bonded creature suffers damage, you can use your reaction to take half of the damage. This damage cannot be reduced or transferred.
• The creature also benefits from Crimson Resilience and Sanguine Shield when you use those Sanguine Arts.
• If the bonded creature is reduced to 0 hit points, you impart a surge of blood energy to prevent unconsciousness. They instead are reduced to 1 hit point and the bond ends.

Blood Form

At 15th level you have perfected your blood magic, able to shroud your body in blood, augmenting your combat prowess. Once per long rest, as an action, you can expend all of your remaining blood dice (minimum three) to enter this Blood Form. You gain temporary hit points equal to twice the total necrotic damage you take by doing this. Your Blood Form lasts for one minute or as long as you have these temporary hit points. While in Blood Form you gain the following abilities and cannot use Sanguine Arts:

• You have advantage on all melee attack rolls.
• You have advantage on Strength and Constitution checks and saving throws, and are immune to poison, the poisoned condition, and necrotic damage.
• On a successful hit with a melee weapon attack, you deal bonus necrotic damage equal to one roll of your blood die and heal hit points equal to the bonus damage dealt.
• If you become paralyzed or stunned, at the start of your turn you can choose to take necrotic damage equal to the effect’s save DC. This damage ignores resistance and immunity and cannot be transferred. If you do, the condition ends and you may take your turn as normal.

If your Blood Form ends as a result of taking damage that would deplete your temporary hit points, you must make a Constitution saving throw. This roll is not affected by the benefits you have in your Blood Form. The DC is your class level plus the amount of blood dice you rolled to enter Blood Form. On a failed save you have the prone and stunned conditions until the start of your next turn and you gain one level of exhaustion.

Sanguine Ascendancy

At 18th level, your mastery of blood surpasses mortal limits. When you roll initiative and have zero Sanguine Arts uses remaining, you regain a number of uses equal to your proficiency modifier and restore all Sanguine Arts uses on both a short and long rest. Your Blood Form also improves, gaining the following abilities:

• When you enter your Blood Form you gain temporary hit points equal to three times the total damage taken instead of two times.
• You no longer require a minimum of three Sanguine Arts uses to enter Blood Form.
• While in Blood Form, you have a flying speed of 60 feet as sanguine wings sprout from your back.
• Your weapon reach increases by 5 feet as long as you are in Blood Form.
• You deal bonus necrotic damage equal to two rolls of your blood die instead of one and heal for that amount.