You have made a pact with an alternate version of yourself from across the multiverse. Different versions of yourself may have varying intentions; some may want to simply assist alternates in gaining strength and security, while others may want to use you to spread their influence across the multiverse. Regardless of intention, this other you has gained enough power in their reality to somehow break universal barriers to communicate with you and lend you their power. 

Patron Spells

The Alternate Self grants you the following benefits:

Prepared Spells. You always have certain spells ready; when you reach a Warlock level specified in the Alternate Self Spells table, you thereafter always have the listed spells prepared.

Free Casting. You can cast one of your prepared spells from this feature without expending a spell slot, and you must finish a long rest before you use this benefit again

Spell Level	Spells
1st	shield, sanctuary
2nd	blur, alter self
3rd	haste, slow
4th	phantasmal killer, greater invisibility
5th	arcane hand, mislead

 

Additionally, you can choose the spell Reality Break as an 8th level Mystic Arcanum.

Borrowed Awareness

Starting at 1st level, you can recall of your Alternate Self's knowledge from their universe. Before you roll an Intelligence, Wisdom, or Charisma check, you can choose to gain advantage on the roll. Additionally, when you roll initiative at the start of an encounter, you can choose to add your proficiency bonus to the roll.

You can use this feature a number of times equal to your spellcasting ability modifier (minimum of once). You regain spent uses after a long rest. 

Supporting Mind

Starting at 6th level, you can call on your Alternate Self to reinforce your mind against influence. When you take psychic damage, you can use your reaction to reduce the damage against you by half. Additionally, when you make a saving throw to resist a mental effect, you can use your reaction to reroll your save. You can do so after seeing initial roll but before any effects occur.

You can use this feature a number of times equal to your spellcasting ability modifier (minimum of once). You regain all uses when you finish a short or long rest.

Second Thought

Starting at 10th level, your Alternate Self can assist you in maintaining your spells' effects. When you cast a spell that requires concentration, you can use this feature to remove that requirement. The spell lasts for its full duration or until you choose to end it. If a spell gains additional benefits from maintaining concentration for its full duration, it no longer gains those effects.

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

Temporal Infraction

Starting at 14th level, you use yourself as a conduit to temporarily bring your Alternate Self into your universe. As an action, you can summon your Alternate Self in an unoccupied space within 30 feet you. They appear as a misty silhouette and have the same game statistics as you, though any magic items they possess do not function. They act on their own initiative and the DM determines their actions. While you and your Alternate Self are within sight of each other, all attack rolls against you both are made with disadvantage. The Alternate Self disappears and returns to their universe after one minute or until they drop to 0 hit points.

Once you use this feature, you can't use it again until after a long rest.