Base Class: Warlock
Your patron is Azathoth, the nuclear chaos, the daemon sultan, the idiot god. He rules at the center of infinity over a mindless horde blind and asleep.
Intelligence Spell Casting:
Instead of having other attributes as your spell-casting ability for your spells, you instead use your intelligence to cast spells with. Additionally, any invocation which uses your another modifier to determine its effects instead uses your intelligence modifier.
Primordial:
You may not prepare spells that inflict Acid, Necrotic, Poison, or Radiant damage. You may not prepare Necromancy spells. You may not prepare spells that heal or bring creatures back to life. You may not prepare spells that transmute or conjure living things. You may not transmute objects into living things. You may not prepare abjurations against specific living creatures. You may not prepare abjurations against specifically Acid, Necrotic, Poison, or Radiant damage. You may not prepare spells that name living organisms, people, or deities as the inspiration or source of their power. Any spell that seems to draw upon strengths outside of the fundamental forces of the universe is not recommended but should be enforced by the player. A judgement by the DM and player can make exceptions to any of the previous rules on a case by case basis.
Expanded Spell List:
Azathoth lets you choose from both the wizard and warlock spell list when you learn a spell. You may take mystic arcana from either list.
Glimpses of the Sultan
Obsessed with your research, you start having dreams and nightmares. Glimpses of a terrifying thing far off in the center of the cosmos pervade your mind. A man made entirely out of wriggling shadows appears sometimes in the surroundings. You grow more and more feverish as the visions increase in frequency. The man appears and guides you to a large black book, a quill, and a knife. Something takes hold of you and you slit your hand open with the knife and sign your name in the book in blood. The fever ends and you gaze upon the sleeping god again. You know that you have sold your soul to it.
You gain a passive boost to intelligence equal to Level/3 rounded down but lose wisdom equal to Level/5 rounded down. You may learn a spell at random of the highest tier you could normally learn every 3rd level.
Dreams Bring the Fever
After signing the book and using more of your abilities you are plagued with nightmares. Your sight is tinged violet as you travel to strange worlds beyond imagination and witness unspeakable things. Some trips horrify you to the point of damaging your mind, others provide inspiration to new ways to alter reality around you.
Starting at 6th level during a long rest, roll a d6. On a 1 or 2 take 1d4 damage. On a 3 or 4 the DM must tell you an unknown fact about the world (it can be entirely mundane or critically important or anywhere in between, DM's choice). On a 5 or 6 make a medium difficulty intelligence check and a hard difficulty wisdom check. If the intelligence check succeeds AND the wisdom check fails you may learn a spell in the lowest tier you don't know in either spell list tier 5 or below.
Visions of Oscillating Multidimensional Curves
You start to notice strange objects in the reality around you. Unable to describe their true characteristics, the best you can say is that they seem to be curves, or perhaps strings that expand in more than the 3 dimensions that you are used to, permeating the space around you. Examining them you begin to believe that you might be able to manipulate them to move through space....
Starting at 10th level, once, until your next long rest, roll a d6. On a 1 nothing happens. On a 2 or 3 teleport to somewhere unobstructed of the DM's choice within 60 meters. On a 4 or 5 teleport to somewhere known (within sight or previously seen) within 60 meters. On a 6 teleport to Azathoth's court for 3 turn cycles. Upon returning prepare your maximum amount of spells instantly and make an intelligence check. If the check succeeds take an additional mystic arcanum of the any tier below or equal to your last mystic arcanum (If you haven't yet taken a mystic arcanum learn an additional 5th tier spell instead).
Entropic Presence
You have gained enough of Azathoth's power that your mere presence warps and fragments the laws of the universe around you. It seems chaotically affect the results of magic cast near you.
Starting at 14th level, whenever a spell (regardless of whether you are dead or alive and regardless of whether the spell is harmful, beneficial, or neutral) is targeted at you or will affect an area within 2 meters of you, roll a d6. On a 1 the spell's numerical values are doubled (if none nothing happens). On a 2 or 3 nothing happens. On a 4 or a 5 the spell's numerical values are halved (if none nothing happens). On a 6 the spell fails (If this seems to overpowered during the playthrough then a 6 will also cancel entropic presence until your next short or long (or maybe just long) rest).