Spoiler: Why I felt like I needed to make Elder Brain stats
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The big one is that an elder brain isn't supposed to be a battle against a giant floating brain shooting off chain lightning or energy waves. An Elder Brain is supposed to be primarily scary not for the power it holds in an upfront fight but because it is the great manipulator of an illithid city state able to orchestrate their actions, able to detect intruders and send minions to strike at them. In direct combat an elder brain is a horrifyingly powerful mind, but that is it. Properly prepared for an elder brain is far from an insurmountable challenge, and an elder brain should not be a challenge for epic level heroes, it should be a battle that can be fought while illithids still serve as usable foot soldiers. In my ideal elder brain encounter the Elder Brain itself is just an "ordinary encounter" (CR = party level), but is itself only a third or even a fourth of the encounter, a host of illithids (12ish) and some more melee brutes bringing up the rest of the encounter. Even then an elder brain is something of a puzzle boss, if properly prepared (Will save boosters, mind blank, [redundant] protection from evil) it is far from the largest threat, but an ill-prepared party is in great danger.


I'll return to making actually new creatures soon, but for now the 3.5 Elder Brain and even the Elder Brain of Thoon failed badly to capture what I feel an Elder Brain ought to be (an immobile tactician) and felt instead like flying doom brains, so I tried to make my own. Not sure about the CR.

Elder Brain
Huge Aberration (Psionic)
Hit Dice: 15d8+150 (217 hp)
Initiative: +7
Speed: 5 ft as a full round action, swim 5 ft as a full round action.
Armor Class: 13 (-2 size, -3 Dex, +4 natural, +4 deflection), FF 13, touch 9.
BAB/Grapple: +11/+19
Attack: -
Full Attack: -
Space/Reach: 10 ft/0 ft.
Special Attack: Mindblast, Psi-like Abilities
Special Qualities: Telepathy (2 miles), Blindsight 120-ft, Darkvision 60-ft, DR 15/magic, Spell Resistance 32 (17 + CR), Dual Existence, Bud Brain Golem, Cyclopean Mind, Psionic Deflection, Peer Through, Astral Distortion
Saves: Fort +15, Ref +3, Will +15.
Abilities: Str 10, Dex 5, Con 26, Int 25, Wis 22, Cha 23
Skills: Bluff +23, Concentration +26, Diplomacy +27, Knowledge (any 4) +37, Knowledge (any other) +19, Sense Motive +25, Spellcraft +25
Feats: Ability Focus (Mind Blast), Ability Focus (Psionic Dominate), Great Fortitude, Improved Toughness x2, MindsightLom, B
Environment: Any land or underground
Organization: Solitary, pair, or cabal (3-6)
Challenge Rating: 15.
Treasure: Double Standard.
Alignment: Always Lawful Evil
Advancement: by Character Class
Level Adjustment: –
Before you is a massive raised pool, 15-ft tall and stinking of brine. Within the pool swims dozens, possibly hundreds, of illithid tadpoles, and amongst them lurks their community’s elder brain. A massive conglomeration of the brains of the dead, fused into one ghastly organism. The massive brain, is 10-ft long, flexible tendrils stretch from it.

Elder brains dwell in massive pools, not always raised, at least 15-ft in diameter and depth, if not more. This means that an elder brain will (almost) always be encountered submerged and attackers will be forced to deal with attacking across the water barrier and possibly even surmounting the 15+ foot wall of the pool; my studies suggest a disintegrate spell as a means of getting around these defenses in a raised pool. An elder brain has between 4 and 8 pseudopods capable of fine manipulations (reach 5-ft), but is physically almost defenseless, barely motile and unable to strike back at foes. Elder brains therefore rely upon guards and their telepathic powers to deal with attackers.

Elder brains exist partially on both the Prime and the Astral Plane. What the purpose of their Astral portion is I do not believe even the illithids know. What is known is that once an elder brain obtains its full size of 10-ft it stops growing on the Prime, instead expanding solely on the Astral Plane. Should an elder brain’s prime material body be slain its astral form continues to exist. I am only presenting game mechanics for their prime body at the present time, I may add their Astral body at a later time, possibly with stats for whether or not their Prime Material body has been destroyed. Certain of Marikus’s notes, that the illithids were initially unwilling to share, state that it was his belief that Ilsensine eats the eldest of the elder brains’ astral forms, and that given a critical mass of brains and age any and all elder brains would become gods and possibly merge into a single gestalt overdeity. Marikus, whose notes normally condemn Ilsensine and the elder brains, showed a single religious moment in response to this, a note of thanks to the Devourer of Secrets for his role in preventing the gestation of this overdeity. I cannot find the basis for Marikus’s beliefs, though, and they may have simply been more of his mad ravings.

Elder brains speak Common, Undercommon, and 7 other languages, but prefer to communicate telepathically.

Combat: An elder brain does not join combat willingly. To battle an elder brain requires that enemies make their way into the very heart of the illithid city. At this point the elder brain will send out a telepathic distress signal to all illithids within a mile, and then proceed to dispel any mental defenses their opponents may possess before releasing a powerful mindblast or psionic dominate to buy itself time for its guard to arrive. Elder brains are rarely found unguarded, brain golems and illithid usually standing ready to protect it.

Mindblast (Ps): This psionic attack is a cone 60 feet long or a burst 20-ft in radius. Anyone caught in this cone must succeed on a DC 24 Will save or be stunned for 3d4 rounds. The save DC is Charisma-based and includes Ability Focus. This ability is the equivalent of a 6th level power.
Psi-like Abilities:
Continuous (reactivation is a free action): Remote View Trap.
At-will: Dispel Psionics (+18 on dispel check), Id Insinuation (DC 22, 5 targets), Ego Whip (DC 24, 4d4 Charisma damage), Adapt Body, Attraction (DC 22, +9 bonus), Aversion (DC 22), Body Adjustment (6d12), Body Purification (6 points), Brain Lock (any type; DC 18), Control Sound, Create Sound, Demoralize (DC 22, 55-ft radius; may center at any point within 50-ft of its actual location), Detect Hostile Intent, Psionic Charm (DC 22, any type, 20 days), Psionic Dominate (DC 24, any combination of augmentations to reach up to 12 Power Points; so 3 humanoid targets for 1 hour, or 2 for 1 day, or 1 aberration, or 2 magical beasts, or a magical beast for 1 day, or a humanoid for 20 days), Psionic Suggestion (DC 22, 6 targets), Read Thoughts, Shatter Mind Blank, Telempathic Projection.
3/day: Hypercognition, Psionic Divination, any three Lv 7 or lower Telepathy, Psychoportation, Clairsentience, or Metacreativity powers (these 3 powers chosen from the Psion and/or Discipline lists upon creation; augmented to 13 PP).
All powers have a ML of 20, but are only augmented to a lower number of power points (usually 13).

Astral Distortion (Su): An elder brain’s presence disrupts the planar connections to the Prime nearby. Any planar travel (including summoning) within 120-ft of the Elder Brain is delayed by 5 rounds unless the Elder Brain chooses to allow it to pass through. Entities attempting to teleport into or out of the region, plane shift, or even move between the Prime and Ethereal Planes find themselves shunted from normal reality for the interval. The elder brain is aware of the number and kind of creatures entering or leaving this area, and where they are going to/from.

Blindsight (Su): An elder brain’s blindsight is psionic in nature and allows it to detect magic auras as Greater Arcane Sight, can penetrate illusions and transmutations as True Seeing within its area, and perceive the alignment of creatures within the area (unless concealed through magical effects).

Bud Brain Golem (Su): An elder brain is able to create brain golems. Doing so is a long and arduous process during which it may not use its Psi-like Abilities. An elder brain will normally keep 1 to 3 brain golems with itself at all time as guards.

Cyclopean Mind (Ex): An elder brain’s psyche is beyond that of normal mortals. An elder brain may treat itself as being in any square within 30-ft as the origin of any psi-like or spell-like ability it uses, and whether its bindsight has line of effect. An elder brain may use Intelligence in place of Dexterity to determine its Initiative. In addition it is immune to mind-affecting effects, and any creature attempting to affect it with a mind-affecting spell, spell-like ability, psionic power, mystery (even if Supernatural), utterance, or similar effect (whether a given Su ability qualifies is up to DM discretion) must make a Will save (DC 23; this DC is charisma based) or lose 4d6 power points and be stunned for 1 round, then confused for 1d4+1 rounds due to the psychic backlash, a creature confused by this effect treats itself as the caster of the confusion effect and can possibly be forced to attack or flee from itself.

Dual Existence: The majority of an elder brain actually exists on the Astral Plane. What is extent on the Prime is merely an extension. This astral portion is well hidden, resisting any divination attempts by beings with less than 11 divine ranks, and cannot normally enter other planes than the Astral. If slain on the Prime the Elder Brain’s consciousness fully re-enters the Astral Plane and it becomes unattached to the Prime. What happens to such an Elder Brain is unknown, probably madness.

Peer Through (Su): An elder brain is able to extend its senses through any willing or dominated creature within its telepathy range. While doing so it uses that creature’s senses, but gains the effects of True Seeing and Arcane Sight, and may Detect [Alignment] through the target. An elder brain may use this ability to see through up to 1 creature per point of Intelligence modifier (minimum 1).

Psionic Deflection (Su): An elder brain is surrounded by a field of psionic force which grants it a +4 Deflection bonus to AC and causes all ranged touch attacks to have a 40% miss chance against it.

Telepathy (Su): An elder brain’s telepathy extends for two miles in all directions through solid stone and other materials which would block line of effect. An elder brain may hold communications with up to 2 creatures per point of Intelligence modifier (minimum 1), and may serve to relay information between telepathic creatures within this area each pair counting as 1 creature communicated with. An elder brain is able to send out simple telepathic signals to any number of creatures at once but must either do so to all creatures with telepathy or all creatures with Int 1 or higher. Such signals are extremely limited in info being more general empathic feelings such as “danger” “fear” “hatred” “anger” “warning of ire”, etc.

Skills: An elder brain gains a +12 bonus to all Knowledge checks and may make Knowledge checks untrained.