The following spells are added to the warlock spell list for you.

The stranger, however, is not as cooperative as you'd like. That's fine, they'll learn soon.

You have nothing to hide, any more - you unlocked the darkest door in your own mind, stared into the abyss, then threw the key into it. The bottomless pit of despair that lies beneath the subconscious of every sentient creature now whines at your heels like a dog.

Your connection to your new friend gives you some interesting powers. From being able to break the minds of others by turning their insecurities against them, to the shaded arts that come from merging yourself with your shadow.

You are a master of your own self - but in a way most would charitably call unhealthy. You have weaponised your own self-hatred into a magical force, an inverse oath against your very nature, with a vigour that gives it form in the real world.

Exposure to such a malevolent force might have broken most other folk, however, you have been studying for such an occasion. Whether through occult magic or sheer force of will, you clapped this creature in psychic chains and made it bend the knee. Now, it serves you.

Whilst most Warlocks seek out eldritch horrors and dark creatures for their patrons, you are different. You have found something shaded in the horrific annals of your own mind - within the dark corners of your insecurities lies a vile stranger who knows every single intimate detail about you.

Dark Double

At 1st level, your dark double manifests itself.

As an action, you may choose to summon your dark double into a space you can see within 30ft of you. This dark double lasts for one minute, or until you fall unconscious, and manifests as a perfect illusion of you. Your dark double must remain within 120ft of you, or it will vanish.

You may use your bonus action to move your dark double, which has your base walking speed. When your dark double passes through a creature, it deals psychic damage equal to your Charisma modifier to that creature. You may only deal damage this way once per turn.

You may cast spells through your dark double as if you were in its space, but you must use your own senses.

Your dark double mirrors your own appearance, but with a darker pallet of colours and bloodshot red eyes. It may have characteristics that emphasise your own insecurities or deepest fears. It can speak and has a personality, but it is malevolent to you. It must bend to your whim, but it will howl the whole way. It may berate you or chastise you for every order you give it.

The only order you cannot give your dark double is for it to be silent.

Once you summon your dark double this feature, you must finish a short or long rest before using it again. At 10th level, you may use this feature twice before requiring a short or long rest to use it again.

Self Loathing

At 6th level, your manifested hatred of your own qualities intensifies.

When you roll a 1 on the d20 for an attack roll against a hostile creature, or on a saving throw, your dark double manifests for a few short seconds to berate you.

You may add double your Charisma modifier to the damage of your next warlock spell or cantrip cast within the next minute. The bonus damage granted by this feature is psychic.

You may only apply the damage once per spell. If your spell already applies your Charisma modifier to its damage, as part of the spell's text or due to an invocation such as agonising blast, you may choose which bonus to add - but you cannot add both.

Darker Double

At 10th level, your dark double becomes stronger. Your dark double gains the following benefits:

It may now pass through and deal damage to an amount of Creatures equal to your charisma modifier. It may only deal this damage once per creature per turn.

In addition, if you cast a spell that requires a Wisdom, Charisma or Intelligence saving throw against a creature that can see your dark double, that creature has 1d4 subtracted from its roll. Creatures that are immune to the frightened condition cannot be effected by this feature.

Maladapted

At 14th level, you and your dark double have reached a twisted understanding of eachother.

Firstly, you may now order your dark double to be silent, if you so wish. It will also no longer loudly berate you, unless you meet the requirements for your self-loathing feature. Chances are very high that it still despises you, however.

Secondly, you may use your action to send your dark double into the mind of a creature within 30ft of you, consuming it until you summon it again with another use of your dark double feature. That creature must make a Wisdom saving throw against your spell save DC.

On a failed save, the creature suffers 5d8 + your warlock level in psychic damage and becomes stunned until the end of your next turn as it grapples with its inner demons. On a successful save, it takes half as much damage and is not stunned.

If this feature kills a creature, your dark double reappears in a space within 30ft of you at the start of your next turn.

You may use this feature once before requiring a long rest to use it again.