School of Forbidden Knowledge

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d%	Effect
01-03	A Fire Elemental takes advantage of your mishap to slip into the material plane. A hostile Fire Elemental appears within 5 ft of you, returning to the Plane of Fire after 1d6 rounds.
04	The Onlooker you were communing with claws into the material plane. A hostile Onlooker appears in an unoccupied space within 10 ft for you, returning to their plane after 1d6 rounds.
05-11	Your ritual accidentally summons 1d4 Lemure for the Abyss. The Lemure(s) automatically return to the abyss after 1d10 rounds or after defeat.
12-20	A blast of force hits you as the ritual fails. Roll 1d10 force damage; you begin the following day with any equivalent amount of damage taken. You can heal this damage.
21-23	As the ritual fails, 1d10 of your life force slips into the Shadowfell. You total Hp is reduced until your next long rest.
24	A Balor follows the energy from your ritual and emerges from the ground beneath you. A hostile Balor emerges from the ground within 5 ft of you, returning to the Nine Hells after 1d6 rounds.
25-29	You glimpse the Yawning Chaos, and your mind temporarily snaps. Roll for Long-term madness
30-35	The vast knowledge of the cosmos surges into your mind, and your mind is momentarily overwhelmed. Roll for short term madness.
36-45	You awoke a slumbering entity, gives you a stern talking to about rudely waking people up. Castigated, you have disadvantage on all charisma check until your next long rest.
46-47	You thrust yourself into a neighboring dimension. You come under the affects of Banishment for three hours.
48-62	You accidentally loan your name to a harmless fey entity, until your next long rest you can only refer to yourself by honorifics, epithets, or monikers.
63-95	The rituals fails and you must wait until the next long rest to attempt the ritual again.
96-00	Until your next long rest, casting Call Familiar summons an Imp, who refuses to function as a familiar unless paid in secrets.

 

Occultist

At 2nd level, your research into the Occult Arts finally bares fruits. Whenever your spellcasting feature allows you to learn or replace a Wizard cantrip or spell of 1st level of higher, you can choose a new spell from the Warlock Spell list or the Wizard spell list. Additionally, you can copy and Warlock spells you discover into your spellbook, if it is of a spell level you can prepare and if you can spare the time to decipher and copy it.

As an Occult specialist, the time and money you must spend to copy a Warlock spell into your spellbook is halved.

Your Mysterious Benefactor

Your interest in the esoteric mysteries of the occult has attracted the interest of an otherworldly being, who - whether out of curiosity, amusement, or malice - has become invested in your growing knowledge. During your travels, your mysterious otherworldly benefactor positioned a book of shadows in your path, allowing you to study the dark magics within.

At 2nd level, whenever you take a long rest, you can take 1 hour and perform an esoteric ritual. After performing the ritual to completion, roll 1d20. If you roll a 1, your rituals fails and you must roll on the Otherworldly Dangers table for the consequences of your mishap. If you succeed, you gain any 4 Eldritch Invocations of your choice from the Warlock's Eldritch Invocations list until your next long rest. If an Eldritch Invocation has prerequisites, you must meet them to learn it. If an Eldritch Invocation requires a level, use your Wizard level for the prerequisite. Your Spellbook functions as a Book of Shadows for the purpose of Eldritch Invocation prerequisites.

Your spellcasting ability for any Eldritch Invocations is intelligence.

Upon reaching 10th level in this class, you can choose 2 additional Eldritch Invocations.

Written in Blood

Your fluency in the forgotten languages your treasured tome and ruins grows, allowing you to decipher nearly any ritual you come across. You can now add any spell you find with the ritual tag into your spell book. Additionally, exposure to these occult scripts has imprinted these languages on your mind; You learn the Eyes of the Rune Keeper Eldritch Invocation, this invocation does not count against your total available invocations, and you have advantage on Int (Religion, Arcane) checks to recall information about the occult. If you failed The Ritual of the Foregone the previous night, then, whenever you attempt to read with this feature,  you must make a DC 13 Intelligence saving throw. If you fail the save, you must on the Short Term madness table.

Furthermore, whenever you cast a spell as a ritual, instead of doubling the casting time, you can take 1d4 piercing + 1d6 psychic damage + spell level. You must possess a Dagger on your person in order to do this.

The Fruits of Obsession

Exposure to the incomprehensible forces beyond the veil has permanently altered your mind. As an action, you let the otherworldly forces flood your mind and glimpse beyond the veil. Until the end of your next turn, you come under the effect of the Devil's Sight, Witch Sight, Eldritch Sight, and Ghostly Gaze. This feature can be used a number of times equal to your Int modifier (min. of 1). You regain all expended uses after a long rest. However, if you have expended all your daily uses, you can roll a DC 13 Int saving throw. If you pass the save, you regain one use of this feature. However, if you fail, you must roll for short term madness. Furthermore, if you attempt the save again before a long rest and fail, you must roll for long term madness. And if you attempt the save a third time and fail, you must roll for indefinite madness.

Writing on the Walls

You've mastered the esoteric texts you pour over enough that you can know write out your own unique rituals and phrases. As an action, you may write one of the following words or phrases with any writing instrument available to you, including ink, chalk, or blood. The effects last until the end of your next long rest.

Enhance. You can cast enhance ability without a spell slot until your next short rest.

Ward. You inscribe a ward upon a door or threshold. Any creature native to different plane of existence that crosses the threshold or interacts with the door instantaneously returns to their native plane.

The Patron's Mark. You write the name of an otherworldly being on your hand. Choose one of the following conditions; Unconscious, Frightened, or Charmed. As an attack, you attempt to reach out and touch another creature. The creature must make a wisdom saving throw against your Spell Save DC or be afflicted with the chosen condition.

Mark of Obsession. You write a mysterious symbol a surface. For 1 hour, any creature that sees the symbol must make a wisdom saving throw against your Spell Save DC or become obsessed with the mark for 1d4 hours - writing the mark on any nearby surface and encouraging others to ponder the symbol as well.

Whenever you write one of these symbols, roll 1d20. On a natural 1, roll on the otherworldly dangers table to see what your actions have attracted or done.