ELDER BRAIN – 5e stats

Large aberration, lawful evil
Huge aberration, lawful evil (suggested)

Armor Class 10
Hit Points 210 (20d10 + 100)
Hit Points (suggested) 230 (20d12 + 100)
Speed 5 ft., swim 10 ft.
Speed (suggested) swim 10 ft.

Proficiency Bonus +5
Proficiency Bonus +8 (5th Edition Advanced Mode)

STRDEXCONINTWISCHA
15 (+2)10 (+0)20 (+5)21 (+5)19 (+4)24 (+7)

Saving Throws Int +10, Wis +9, Cha +12
Skills Arcana +10, Deception +12, Insight +14, Intimidation +12, Persuasion +12
Skills (suggested) Arcana +10, Deception +12, History +10, Insight +14, Intimidation +12, Investigation +10, Nature +10, Persuasion +12, Religion +10
Senses blindsight 120 ft., passive Perception 14
Languages understands Common, Deep Speech, and Undercommon but can’t speak, telepathy 5 miles
Challenge 14 (11500 XP)

Creature Sense. The elder brain is aware of the presence of creatures within 5 miles of it that have an Intelligence score of 4 or higher. It knows the distance and direction to each creature, as well as each one’s Intelligence score, but can’t sense anything else about it. A creature protected by a mind blank spell, a nondetection spell, or similar magic can’t be perceived in this manner.

Innate Spellcasting (Psionics). The elder brain’s innate spellcasting ability is Intelligence (spell save DC 18). It can innately cast the following spells, requiring no components:

Legendary Resistance (3/Day). If the elder brain fails a saving throw, it can choose to succeed instead.

Magic Resistance. The elder brain has advantage on saving throws against spells and other magical effects.

Psionic (suggested). The Elder Brain has 550 (20d12 + 420) PSPs and can use the following psionic powers, mental attacks and mental defenses:

Telepathic Hub. The elder brain can use its telepathy to initiate and maintain telepathic conversations with up to ten creatures at a time. The elder brain can let those creatures telepathically hear each other while connected in this way.

ACTIONS

  • Tentacle. Melee Weapon Attack: +7 to hit, reach 30 ft., one target. Hit: 20 (4d8 + 2) bludgeoning damage. If the target is a Huge or smaller creature, it is grappled (escape DC 15) and takes 9 (1d8 + 5) psychic damage at the start of each of its turns until the grapple ends. The elder brain can have up to four targets grappled at a time.
  • Mind Blast (Recharge 5-6). The elder brain magically emits psychic energy. Creatures of the elder brain’s choice within 60 feet of it must succeed on a DC 18 Intelligence saving throw or take 32 (5d10 + 5) psychic damage and be stunned for 1 minute. A target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
  • Psychic Link. The elder brain targets one incapacitated creature it can perceive with its Creature Sense trait and establishes a psychic link with that creature. Until the psychic link ends, the elder brain can perceive everything the target senses. The target becomes aware that something is linked to its mind once it is no longer incapacitated, and the elder brain can terminate the link at any time (no action required). The target can, use an action on its turn to attempt to break the psychic link, doing so with a successful DC 18 Charisma saving throw. On a successful save, the target takes 10 (3d6) psychic damage. The psychic link also ends if the target and the elder brain are more than 5 miles apart, with no consequences to the target. The elder brain can form psychic links with up to ten creatures at a time.
  • Sense Thoughts. The elder brain targets a creature with which it has a psychic link. The elder brain gains insight into the target’s reasoning, its emotional state, and thoughts that loom large in its mind (including things the target worries about, loves, or hates). The elder brain can also make a Charisma (Deception) check with advantage to deceive the target’s mind into thinking it believes one idea or feels a particular emotion. The target contests this attempt with a Wisdom (Insight) check. If the elder brain succeeds, the mind believes the deception for 1 hour or until evidence of the lie is presented to the target.

LEGENDARY ACTIONS

The elder brain can take 3 legendary actions, choosing from the options below. It can take only one legendary action at a time and only at the end of another creature’s turn. The elder brain regains spent legendary actions at the start of its turn.

  • Tentacle. The elder brain makes a tentacle attack.
  • Break Concentration. The elder brain targets a creature within 120 feet of it with which it has a psychic link. The elder brain breaks the creature’s concentration on a spell it has cast. The creature also takes 1d4 psychic damage per level of the spell.
  • Psychic Pulse. The elder brain targets a creature within 120 feet of it with which it has a psychic link. Enemies of the elder brain within 10 feet of that creature take 10 (3d6) psychic
    damage.
  • Sever Psychic Link. The elder brain targets a creature within 120 feet of it with which it has a psychic link. The elder brain ends the link, causing the creature to have disadvantage on all ability checks, attack rolls, and saving throws until the end of the creature’s next turn.

5th Edition Advanced Mode
Limiting the power of a character and making the overall difficulty of the game harder, does not reduce the creativity, indeed it does quite the opposite.
The Game Master has the option to use any and all of the instances proposed in this guide, or just some of them according to their preference.

It is the lack of something that move and motivate characters, not the abundance of it

DESCRIPTION

The elder brain is a colossal, sentient mass of brain tissue that floats in a saline pool at the heart of a mind flayer city. It is composed of the brains of deceased mind flayers, who willingly sacrificed their individuality to join the collective consciousness of the elder brain. The elder brain’s psychic powers are immense, making it glow and pulsate with mental energy. It can live indefinitely, as long as it receives new brains to sustain its growth and intellect.

Elder brains perceive the world through their innate telepathy, which extends up to 5 miles for the oldest specimens. They can detect any unshielded sentient being within this range, even through solid rock. They can also communicate with any creature using their telepathy, or spy through the eyes of any creature that they have dominated or persuaded to serve them. However, their perspective is skewed towards the mental plane, where they seek to impose their will and vision.

COMBAT

An elder brain can create a brain golem, a physical extension of itself, by budding a part of its own mass. It can create up to three brain golems, each taking one hour of uninterrupted concentration to form. During this process, the elder brain spends 1d10 PSPs per HD of the brain golem and cannot use any psychic abilities other than communication.

An elder brain rarely needs to create a brain golem, as it has access to the combined psionic knowledge of hundreds of mind flayers. It can use its psionic abilities at double the normal range, making it a formidable opponent for any intruder.

To reach the elder brain in melee, an attacker must enter its pool, a 30-foot-wide by 30-foot-deep basin filled with brine. The elder brain floats 10 feet below the surface, making it immune to normal missile attacks. However, most spells can still affect it, as long as the caster has line of sight and the spell does not change in water.

If the elder brain faces certain death, it retreats to the Astral Plane, where most of its mass resides. However, this means that it loses its connection to the Prime Material Plane and its mind flayer community. It becomes a rogue creature, wandering the Astral Plane without purpose. The mind flayer city that loses its elder brain soon falls into chaos and decay.

HABITAT / SOCIETY

The elder brain is the core of its mind flayer community, providing guidance and wisdom as well as storing the community’s technology, history, and psionic expertise. It is the duty and privilege of every mind flayer to join the elder brain after death, becoming part of its collective mind and sharing its vision for the mind flayer race. Although most mind flayers hope to preserve their individuality after the merger, their egos are overwhelmed by the dominant consciousness that permeates the brain mass.

ECOLOGY

An elder brain feeds on the psionic essence of the tadpoles that share its pool, absorbing their latent potential to sustain its own existence. Even though it constantly adds new mind flayer brains and tadpole life force to its mass, the elder brain never grows larger than 10 feet in diameter. It transfers any excess mass to a node on the Astral Plane, where it maintains a psionic link.