In the first age, in the first battle, when the shadows first lengthened, one stood burned by the embers of Armageddon, his soul blistered by the fires of Hell and tainted beyond ascension, he chose the path of perpetual torment. In his ravenous hatred he found no peace; and with boiling blood he scoured the Planes seeking vengeance against the dark lords who had wronged him. He wore the crown of the Night Sentinels, and those that tasted the bite of his sword named him, the "Doomatic Blood and Guts Puncher". 

Blood Punch

Starting at 3rd level, if you use an unarmed strike against any creature, you can spend one ki point to make a large wave of pure light comes out from the back of the creature and hits any creature in a 15ft cone behind the original creature, dealing 2d6+1 radiant damage. You gain 1d6+1 radiant damage at 6th level, 10th level, 14th level, and finally at 18th level. 

Forged in Hell

Beginning at 6th level, you gain advantage against being charmed or frightened and immune to being charmed or frightened against Aberration, Celestial, Fiend or Undead monsters. If you are charmed or frightened, the creature that has charmed or frightened you are dealt 2d4 radiant damage per round until the effect stops.

Rip and Tear

Beginning at 6th level, if you are within 5ft of a stunned or paralyzed creature, you can use a bonus action to brutalize them, dealing 2d4 + your monk level in bludgeoning damage to the creature. This damage cannot be reduced in any way.

Empowered Abilites

Beginning at 11th level, you gain one of these three benefits for one minute. You can only use these three times in total before needing to take a long rest.

• For two rounds, If you roll a 4 or lower, it is counted as a 5
• You gain resistance to all types of damage except physic and bludgeoning damage.
• Your unarmed strikes count as magical weapons and deal an extra d10 bludgeoning damage. You can also make 3 attacks when you take the attack action if all three attacks are unarmed or with monk weapons.

Mark of Doom

Beginning at 11th level, you can use a bonus action to magically manifest a Mark of Doom on a Creature you can see within 30 ft. of you. The Mark of Doom lasts until the Creature is destroyed, you dismiss it as a bonus action, or until you’re incapacitated and cannot be used again until the next dawn.

The Mark of Doom deals 1d6 Necrotic Damage at the start of the creatures turns, which heals you for the amount of damage dealt. You can also roll 1d6 and subtract that from the damage roll of the Creature if it targets you for an attack or spell attack.

(The damage die increases to 2d6 at 17th level, 3d6 at 13th level and 4d6 at 20th level.)

Blood Rite

Beginning at 17th level, you can deal damage to yourself to deal bonus Necrotic damage to one of your Damage Rolls this turn. You deal 1d10 damage to yourself and deal that amount of Necrotic Damage to the Target, If the Target is Inflicted with Mark of Doom the damage increases to 1d20.

You can use this feature a number of times equal to your Wisdom or Dexterity modifier (You choose). You regain all expended uses when you finish a long rest.

Unmaykr of Doom

Beginning at 17th level, you can make a creature inflicted with Mark of Doom throw itself in front of an attack directed at another creature that you can see. Before the attack roll is made, you can use your reaction to teleport the Mark of Doom inflicted Creature to an unoccupied space within 5 feet of the targeted creature. The attack roll that triggered the reaction is instead made against the Mark of Doom inflicted Creature.

Once you use this feature, you can’t use it again until you finish a short or long rest.