The Cerebrilith

Your mind has been infected by a demon with incredible psionic powers. Perhaps you accidentally opened its prison on one of your adventures into realms best left forgotten, or maybe the demon sought you out after its old host died. Whatever the case, the two of you are irrevocably interconnected, functionally acting as one being. The demon whispers promises of power, which you may or may not be able to ignore. But one undeniable fact has become clear- the demon wants to hunt.

Expanded Spell List

The Cerebrilith 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.

Cerebrilith Expanded Spells

Spell Level	Spells
1st	hunter's mark, longstrider
2nd	detect thoughts, pass without trace
3rd	clairvoyance, nondetection
4th	greater invisibility, locate creature
5th	dominate person, telekinesis

Cerebral Surge

At 1st level, you can tap into a fraction of the cerebrilith's latent psionic power. At the start of your turn, you may trigger Cerebral Surge and gain the following benefits until the end of your turn: 

• When you cast a warlock spell with a casting time of 1 action, you can choose to cast it as a bonus action instead 
• You can reroll damage dice from your warlock spells, keeping the new result each time, up to a maximum of your Charisma modifier per turn (minimum of 1)

You can use this feature once, and then you can't use it again until you finish a long rest. You gain an additional use of this feature when you reach 3rd, 5th, 7th, and 9th levels in this class. When you reduce a creature with an Intelligence score of 10 or higher to 0 hit points, you regain one use of this feature as the cerebrilith devours its intellect. You can only regain uses of this feature once per minute.

Opened Mind

Starting at 6th level, the cerebrilith teaches you how to conjure knowledge of mystic spells normally unavailable to you. When you finish a short or long rest, choose a spell of a level you can cast using warlock spell slots and that is in the school of divination or enchantment. You know this spell until you choose a different one with this feature.

If the spell you chose is on your warlock spell list, you can cast it normally, or you may choose to expend a use of Cerebral Surge and cast it without expending a spell slot or material components with no gold value. You can only cast a spell in this way once before finishing a long rest.

If the spell you chose is not on your warlock spell list, it is a warlock spell for you while you know it, and you can only cast it by expending a use of Cerebral Surge. Additionally, you take 1d8 psychic damage for each level of the spell as soon as you finish casting it. This damage ignores resistance and immunity.

Psionic Resilience

By 10th level, the cerebrilith's psionic powers have bolstered your mental defenses. You have proficiency with Intelligence saving throws, your Intelligence score cannot be lowered, and you are immune to madness effects.

Mind Hunter

Starting at 14th level, you are able to fully realize the cerebrilith's psionic potential. When you use cerebral surge, you may choose a number of creatures you can see within 90 feet, up to your Charisma modifier (minimum of 1). Each target must make an Intelligence saving throw. Creatures that are immune to psychic damage or have an intelligence score of 2 or lower are unaffected. Pass or fail, the creature takes 2d6 psychic damage. On a successful save, the creature suffers no other effects.

For every creature that failed, choose any number of effects from the list below, affecting all creatures at once. For each effect chosen beyond the first, you instantly take 1d8 psychic damage per affected creature.

• The creature takes an additional 4d6 psychic damage
• You have advantage on attack rolls against the creature until the end of your turn
• The creature's movement speed is halved, and it can't take reactions until the end of its next turn

You can't use this feature again until you finish a long rest.