Ratling Hive Brain

Gargantuan aberration, chaotic evil

Physical Description

The ratling hive brain defies conventional biology, representing the ultimate fusion of multiple ratling consciousnesses into a single, immense entity. At the center of its mass is a giant, pulsating brain-like structure that glows with psychic energy, surrounded by a constantly shifting amalgamation of partially formed ratling bodies in various stages of absorption and integration. Dozens of eyes of different sizes blink independently across its surface, each one linked directly to the central neural mass. Multiple limbs—some fully formed, others mere stumps—protrude from its bulk, occasionally acting with purpose but more often twitching in response to the brain's overwhelming psychic emanations. The entire entity hovers above the ground, surrounded by a nimbus of psionic energy that distorts light and sound in its vicinity. When it communicates, it speaks not through a single mouth but through a chorus of partially formed vocal organs that create a disturbing harmonic effect.

The chamber ahead pulsates with sickly light, revealing a horror beyond comprehension. Floating at its center is a massive, glistening organ that resembles a brain the size of a small house, surrounded by a constantly shifting mass of partially formed ratling bodies being absorbed into its bulk. Countless eyes of various sizes open and close across its surface, each movement synchronized to patterns of energy that course through its neural tissue. The air itself feels thick with psychic pressure that makes thought increasingly difficult the closer one approaches. When it notices your presence, dozens of voices speak simultaneously from all around its bulk, creating a chorus of words that bypass your ears and materialize directly within your mind.

Lore

Collective Consciousness. The hive brain represents the ultimate evolution of ratling hive mind technology—a massive psychic entity created through the fusion of hundreds or thousands of individual ratling minds into a single, vastly more powerful consciousness. Each contributing mind adds its memories and capabilities to the collective, though individual personalities are eventually subsumed into the greater whole.

Psychic Nexus. Hive brains serve as the central coordination points for entire networks of ratling warrens, extending their psychic influence across vast distances to direct activities and gather information. This network allows for unprecedented coordination among typically chaotic ratling societies, enabling complex, long-term strategies that would be impossible for normal ratling hierarchies to maintain.

Knowledge Repositories. Each hive brain contains the accumulated knowledge of every mind absorbed into its mass—including the complete memories of generations of ratling leaders, shamans, and warriors. This makes them invaluable repositories of historical and magical knowledge, though extracting specific information from their consciousness can be difficult due to the sheer volume of competing memories.

Reality Shapers. The most powerful hive brains develop the ability to directly manipulate reality through concentrated psychic effort, reshaping matter, altering probability, or even creating localized pocket dimensions. These abilities typically develop as the brain absorbs more powerful minds, particularly those with innate magical talents or psionic potential.

The Joining

"The ritual of joining is simultaneously the greatest honor and the ultimate sacrifice in ratling society. Selected individuals—typically those who have demonstrated exceptional mental capabilities or leadership potential—are brought before the hive brain and psychically consumed, their bodies and minds gradually absorbed into its mass. The process takes weeks, during which the subject remains conscious, experiencing the gradual dissolution of their individual identity as they merge with the collective. Those who resist are simply broken and consumed anyway, their memories preserved but their consciousness destroyed." — Account from a half-mad survivor who escaped a hive brain chamber

Stats

• Armor Class: 24 (natural armor)
• Hit Points: 600 (50d12 + 250)
• Speed: 20 ft., fly 60 ft. (hover)

STR	DEX	CON	INT	WIS	CHA
26 (+8)	16 (+3)	30 (+10)	28 (+9)	24 (+7)	24 (+7)

• Saving Throws: Int +17, Wis +15, Con +18
• Skills: Arcana +17, Insight +15, Perception +15, History +17
• Damage Resistances: cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks
• Damage Immunities: poison, psychic
• Condition Immunities: charmed, frightened, paralyzed, poisoned, prone, stunned
• Senses: Truesight 120 ft., passive Perception 25
• Languages: All, telepathy 300 ft.
• Challenge: 25 (75,000 XP)

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

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

Psychic Shield. The hive brain generates an aura within a 30-foot radius. Any ally within this radius gains advantage on saving throws and is resistant to psychic damage.

Telepathic Hub. The hive brain can communicate telepathically with any creature it has seen before, provided that creature is on the same plane of existence. It can maintain telepathic communication with up to 100 creatures simultaneously.

Innate Spellcasting (Psionics). The hive brain's innate spellcasting ability is Intelligence (spell save DC 25). It can innately cast the following spells, requiring no components:

• At will: detect thoughts, levitate, telekinesis
• 3/day each: dominate monster, feeblemind, mass suggestion, teleport
• 1/day each: gate, imprisonment, psychic scream

Multiattack. The hive brain makes three psychic blast attacks.

Psychic Blast. Ranged Spell Attack: +17 to hit, range 120 ft., one target. Hit: 45 (8d6 + 9) psychic damage.

Mind Control (Recharge 5–6). The hive brain targets one creature it can see within 60 feet. The target must succeed on a DC 25 Wisdom saving throw or be charmed for 1 hour. While charmed in this way, the creature is under the hive brain's control and can communicate telepathically with it. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Dominate Ratling. The hive brain can force one ratling creature within 300 feet to act as if it were under the effect of the dominate monster spell (no save).

Mind Consumer (Recharge 6). The hive brain targets one creature it can see within 30 feet. The target must make a DC 25 Intelligence saving throw. On a failure, the target takes 78 (12d12) psychic damage and the hive brain gains access to all of the target's memories and knowledge. On a success, the target takes half as much damage and the hive brain does not gain access to its memories. If a creature is killed by this attack, the hive brain can choose to absorb its consciousness, permanently gaining one skill or language proficiency that the target possessed.

Legendary Actions

The hive brain can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The hive brain regains spent legendary actions at the start of its turn.

Psychic Blast. The hive brain makes one psychic blast attack.

Psychic Wave (Costs 2 Actions). The hive brain emits a psychic wave. Each creature within 60 feet of it must make a DC 25 Intelligence saving throw, taking 36 (8d8) psychic damage and being stunned for 1 minute on a failed save, or half as much damage and not stunned on a successful one. A creature can repeat the saving throw at the end of each of its turns, ending the stun effect on itself on a success.

Summon Minions (Costs 3 Actions). The hive brain telepathically summons 1d6 Ratling Warbringer to appear in unoccupied spaces within 60 feet of it. These ratlings act on the hive brain's initiative and obey its telepathic commands. They remain until killed or until the hive brain dismisses them as a bonus action.

Lair Actions

On initiative count 20 (losing initiative ties), the hive brain takes a lair action to cause one of the following effects; the hive brain can't use the same effect two rounds in a row:

Psychic Assault. The hive brain targets up to three creatures it can see within its lair. Each target must succeed on a DC 20 Intelligence saving throw or take 16 (3d10) psychic damage and be stunned until initiative count 20 on the next round.

Reality Warp. The hive brain warps reality around it. The area within 100 feet of the hive brain becomes difficult terrain until initiative count 20 on the next round. Additionally, each creature in that area must succeed on a DC 20 Wisdom saving throw or be disoriented, having disadvantage on attack rolls until the end of its next turn.

Memory Drain. The hive brain targets one creature it can see within its lair. The target must succeed on a DC 20 Wisdom saving throw or forget one important fact or piece of information (determined by the DM) and be unable to recall it for 24 hours.

Tactics

The ratling hive brain begins combat by using its telepathic abilities to assess threats and coordinate allied ratlings throughout its lair. It remains at a safe distance, using Psychic Blast to attack from range while employing Mind Control against the most physically powerful enemies. The hive brain uses its legendary actions strategically—employing Psychic Wave when multiple enemies are clustered together and Summon Minions when it needs additional protection. Against particularly dangerous foes, it will use Mind Consumer to both damage them and gain tactical information about their capabilities. The hive brain fights with the accumulated tactical knowledge of countless absorbed minds, allowing it to quickly identify and exploit weaknesses in enemy formations and strategies. If seriously threatened, it will use Teleport or Gate to escape, often to a secondary lair prepared specifically for such contingencies.

The massive brain pulses with psychic energy as it simultaneously coordinates dozens of ratling minions while launching precise mental attacks against priority targets. Lesser ratlings move with perfect synchronization, as if controlled by invisible puppet strings, while waves of psychic force distort reality around the central mass. The multitude of eyes across its surface scan in different directions, processing information from multiple perspectives and timelines simultaneously. Its telepathic voice resonates with the harmonics of countless absorbed minds, each contributing fragments of knowledge and tactical insight to the collective consciousness.