The secret keeper

In a search for knowledge unknown to the rest of the world, you searched far and wide for a teacher older then the mountains and the race of elves. When you found your teacher, they revealed themself as a powerful being from the beginning of time. But what you likely don’t know is that they are chained, and imprisoned in a timeless dimension, and very mission you complete for them is to help them escape. As you gain their trust and complete more missions, the more forgotten knowledge they bestow upon you, but be weary. Their time imprisoned has driven them mad, no matter how good they were before, and their knowledge has been warped, and their secrets come with a terrible price.

Forgotten arcana

Your patron teaches you versions of existing spells through more powerful techniques forgotten by time. Your learn 2 spells of your choice from any classes spell list of levels you can cast, these spells don’t count against the number of spells you know. For you, spells you choose this way count as if they were cast one spell slot higher than they actually were, but when you cast them the warped form of the knowledge shakes your mortal body, and deals necrotic damage to you equal to you level. You gain this benefit again at 3rd, 5th, 7th, 9th, 11th, 13th, and 15th level.

Secret keeper Expanded Spell List

The Secret keaper lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

Fiend Expanded Spells

Spell Level	Spells
1st	chaos bolt, bane
2nd	alter self, blur
3rd	animate dead, blink
4th	Evard’s black tentacles, Death ward
5th	antilife shell, wall of force

Knowledge of the secret keaper

At 6th level, your patron teaches you thing most people don’t have access to. You gain proficiency in two intelligence skills of your choice, and expertise in history. You also gain proficiency in intelligence saving throws.

Mind warper

Starting at 10th level, you can strike a creature with the madness of your patron. As an action on your turn, you can make a creature make a  wisdom saving throw equal  to your spell save DC. If they fail, they are dealt 3d10+4 psychic, and are stunned for 30 seconds. You may use this ability a number of times equal to half your proficiency bonus rounded down, and regain all expended uses when you finish a long rest.

Supreme knowledge

At 14th level, your patron teaches you a vast number of things. When you fail a intelligence or charisma saving throw, you can choose to succeed it instead and take 10 necrotic damage. Additionally, when you see someone cast a spell, you can make a dc18 intelligence saving throw, that you may not chose to succeed with the first feature granted by this ability. If you succeed, you learn that spell.