Upon taking up the mantle of Death Knight, you gain all the powers and prowess that comes with it, You will learn to become the Death reincarnate. 

Profanities

At level 3, when you choose to take on the mantle of Death Knight, you learn a number of profanities equal to 1 + your Charisma modifier (minimum 1), chosen from the list below. When you activate a profanity, a dark colored aura surrounds you imbuing you with the specific profanities bonus. You can use a bonus action to activate or deactivate one profanity. Falling unconscious will deactivate all profanities active. Activating a profanity while you have one already active will automatically deactivate the previous one. At level three you can only benefit from one profanity at a time, two at level 5, three at level 12, and four at level 18, and the profanity effect will stay active until it is deactivated, or on the subsequent failed saving throw. At the end of each of your turns in combat, while you have more than one profanity active, you must pass a DC 15 Constitution Save, or one random profanity will deactivate.

Aura Of The Damned

Any enemy creature within 20 feet must make a constitution saving throw or be at disadvantage on attack rolls made against you

Deathly Glamour

You can add your Charisma modifier to all ability saves

Grave Armor

Gain +2 AC against enemies that are making melee attacks against you

Pale Horse

You summon a ghostly looking horse. You increase your speed by 10 feet.

Soulflay

A creature you choose within 30 feet of you have disadvantage on a single saving throw of your choice.

Soulreaver

The weapon you hold becomes bathed in the essence of your aura . The weapon must be a bound weapon(see below). On a successful melee attack add an additional 1d4 of necrotic damage. Increases to 1d6 at level 6, and 1d8 at level 10.

Terrorize

If a creature moves to within 30 feet of you, you can use your reaction and the creature must succeed on a Wisdom saving throw or become frightened of you for 1 minute. The DC is equal to 8 + your Strength modifier + your proficiency bonus. Whether successful or not, a creature cannot be targeted by this ability again until you finish a long rest.

Bound Weapon

At 3rd level, you learn a ritual that creates a magical, living bond between yourself and one weapon. You perform the ritual over the course of 1 hour, which can be done during a short rest. The weapon must be within your reach throughout the ritual, at the conclusion of which you touch the weapon and forge the bond. Once you have bonded a weapon to yourself, you can't be disarmed of that weapon unless you are incapacitated. If it is on the same plane of existence as you, you can summon that weapon as a bonus action on your turn, causing it to instantly materialize in your hand, unless it is held by a greater power. In addition, you may also absorb its physical form within your very being, which may act as an effective storage place. You can have up to two bonded weapons, but can summon only one at a time with your bonus action. If you attempt to bond with a third weapon, you must break the bond with one of the other two. You gain a +1 bonus to all attack and damage rolls with your bound weapon.

Etherfloat

You hover a few inches from the ground. You do not trigger pressure plates or the like; you can cross liquid surfaces if they are still; and you descend to the ground harmlessly as if under the effect of the 'Feather Fall' spell.

Siphoning Strikes

At 7th level, you learn to control the balance of life and death within yourself. When you reduce a creature to 0 hit points, you gain temporary hit points equal to your Charisma modifier. Your current value is also affected by this. These bonus hit points expire at the end of the battle, and you return to the hit point amount, scaled at a 1 to 1 ratio, of what you had by the end of the battle. For example, if your original max HP was 20, and you gained 10 hit points, but was reduced to 15 (15 out of 30 HP total), then you would result with 10 out of 20 hit point

Shadow Meld

At 10th level, as an action you may teleport to a point you can see within 60 feet if you and that point are both in darkness. You may also take one other creature with you. If the creature is not willing, it must succeed on a Dexterity saving throw to evade you. DC being 8 + your Constitution modifier + your proficiency bonus. Additionally, you gain resistance to necrotic damage while you have a profanity active.

Death's Embrace

At 15th level you have come to know that even to the strongest, Death is inevitable. If damage reduces you to 0 hit points and doesn't kill you out right, you may make a Constitution saving throw with a DC equal to the damage done. On a success, you drop to 1 hit point instead. You may use this ability once per long rest.

Revenant

At 18th level, you fully assume to the mantle of Death Knight; you no longer require food, water, or sleep. You may still gain the benefits of a long rest if you spend 8 hours undertaking light activities such as reading or keeping watch. Additionally Starting at level 18, when a friendly creature within 30 feet of you is knocked unconscious and not outright killed, it can choose to drop to 1 hit point instead, and gain temporary hit points equal to your Fighter level + your constitution modifier (a minimum of 1).You must finish a Long rest before this feature may be used again.