The Black Knight

From darkness and given powers from a powerful patron this knight uses its powers to cast fear into those it fights. Using its abilities to cast mortal doubt in its enemies and strike its enemies when they are at their meekest. They use every advantage afford to them and will make their enemies beg for mercy.

Level 3: Frightful Visions

When you are at a location where there was violence, trauma or danger, you can see visions of what has transpired. You can see events in shades of grey, faces are not distinct but you do sense emotions from those in the conflict. You can't hear specific voices but you do feel intent. If the DM chooses you can perceive more information. You can use to a number of times up equal to your proficiency bonus. 

As a part of this ability you gain immunity to being frightened.

Level 3: Terrible Transformation

Through time spent in dark reflection, you have taken the power from either your own will or from another creature's help, you can transform your body into an instrument of fear. As a bonus action, you transform for 1 minute. If you are knocked unconscious you transform back to your normal self. 

You gain the following benefits while transformed:

• When transformed you can stack one additional ability that gives you temporary HP. You can choose which ability will deplete first when hurt and you can choose which source you would like to keep if you need to choose from multiple sources. Once you have used this benefit once, you will need to transform again to access this ability again. 
• You gain temporary hit points, Constitution modifier (Max 5) times your fighter level. The temporary hit points will disappear when the transformation ends. 

• Being a source of fear manifest, you have advantage on intimidation checks

• As a part of the transformation, you can cast Thaumaturgy as a free action. 

Afflictions. These are abilities that you can do while you are transformed. They are not accessible outside of your transformation. As part of these abilities anything that requires a save can use your mortal strike DC.

• Dishonorable Strike - Take 1d10 of force damage to take one additional opportunity attack. This could be on the same or different creature and you can only use this once per turn and only after you used a reaction and not at a separate time in the same round.

• You’re next. - After you have killed a creature with the frightened condition, use your reaction to force one target you can see within 60 ft to make a Wisdom saving throw against your mortal strike DC. If they fail, they now have the frightened condition. 

• Surprised? - Use bonus action and take 1d10 force damage to disappear and reappear in front or behind a creature you can see of your choice. The range of this ability is within 30 feet but if the creature is frightened of you, it has a range of 60.

Level 3: Mortal Strike

You strike your foe with a magically tinged attack, the victim feels an existential fear well up within them. This attack is intentionally intimidating, using brute strength to overwhelm the target. Once per round, you make a weapon attack against one target. On a hit, the target suffers the weapon attack’s normal effects, and will need to make a strength saving throw. On a failure the creature will have a mortal fear overwhelm them, they will also take 1d8 psychic damage as part of the attack and they will be frightened for one minute. This ability is not tied to your transformation and you do not need to be transformed to access mortal strike. 

To determine the DC (8 + Proficiency + Strength) If they succeed, they are not frightened and will only take half of the psychic damage. If the target is frightened and ends its turn in a space where it doesn’t have line of sight to you, the creature can make Wisdom saving throw against the original DC. On a successful save, the creature is not frightened.

This spell’s damage increases when you reach certain levels. At 5th level, the melee attack deals an extra 1d8 psychic damage to the target on a hit, and the psychic damage to the second creature increases to 1d8. Damage rolls increase by 1d8 at 5th level (2d8) 11th level (3d8) and 17th level (4d8).

Level 7: Death Glare

With a single look you can make droves of enemies shiver in fright. You tell them with a glance what is coming next. As a part of this ability you can cast the Fear spell. You cast it as an attack rather than an action and it counts as an innate ability and not a spell. You can only use it once per turn and you can only use this ability a number of times equal to your proficiency modifier. This will will cost 2d10 of force damage to use.

Level 10: Additional Afflictions

When you are transformed you have access to these new abilities on top of what you already have access to. 

Existential Threat. Take 1d10 force damage to bypass resistance to being frightened when using mortal strike or death glare. This ability doesn't affect any creature with immunity. 

Get over there. Take a reaction and 1d10 force damage to force a frightened creature to run in a direction of your choosing. This includes dangerous and potentially fatal situations. They will need to make a wisdom saving throw against your mortal strike DC. 

Beg for Mercy. After a mortal strike or a death glare, force a creature to make a wisdom saving throw against your mortal strike DC. If they fail, you can choose one of these three effects. They drop what they have in their hands, they go prone, or their movement speed is zero. These effects will last until the end of your next turn.

Level 15: Fear the Reaper

When you transform, any creature you choose in a 15 foot radius will need to make a wisdom save against your Mortal strike DC, if they fail they will have the frighten condition.

Level 18: The Mind Killer

When you frighten a creature, take 2d10 to paralyze the creature instead. A creature paralyzed in this way can make a saving throw at the end of their turn to end the paralysis but they will still have the frightened condition.