Ilsensine

seIlsensine (meaning "great brain" or "powerful brain" in Undercommon)  was the patron deity and creator of the illithids, and the Tentacled Lord  embodied their ideals of mental prowess, unlimited knowledge, and willful dominion over all other lifeforms. Although predominantly focused on mind flayers, the God-Brain was the patron of all beings that enslaved the thoughts of others.

Ilsensine was known as such by the sages and scholars of most races, but illithids identified them differently. Rather than a name, telepathically communicating mind flayers used a series of visual images and symbolic denotations to represent it. A psionic inflection used to mark Oryndoll as a holy place of Ilsensine was enough to cause fear in those minds the name was projected into.

"Knowledge is the only power."

- Ilsensine

Description
A being of the mind and spirit, Ilsensine lacked any physical body, instead incarnating as a cohesive thought. Radiating a lambent, emerald hue this manifestation took the shape of a gigantic, pulsing mass of cerebral matter. As was depicted by the mind flayers and as was actually the case, around the disembodied, brain-like form was a number of ganglionic tendrils radiating outwards in all directions, immeasurable in length and uncountable in number. Running along surfaces and through the earth, the God-brain's tentacles extended beyond sight and to all the nigh-infinite reaches of the multiverse.

When incarnating in an avatar, Ilsensine's floating form was much easier to comprehend, appearing as spectral across, green-glowing brain with only two tentacles.

Personality
Alien and elusive, Ilsensine's thoughts were a relentless tide of dark deceptions and unimaginable deviancy. According to elven myths, before the creation of mortal beings, it surpasssed all its divine peers in subversive intent, always striving to undo what others accomplish and defy established convention, and even loosing the mind flayers to act as a counter-creation after mortals came into existence. It was a cold and calculating being of practically limitless knowledge, and its philosophies mirrored that of the illithids, holding information as the greatest commodity, darkness the greatest illumination, and the mind the greatest strength.

Another dominating facet of Ilsensine's unending thoughts was megalomania for its motivation was the supremacy of the greatest race in its mind; its own illithid creations. Of all those that it knew of, it judged them the most worthy mortals, and sought for them to conquer all planes. Its thoughts unceasingly insisted that they were meant to rule all reality, enslaving, using and consuming the rampant "cattle", and enjoying the conquest as they did so. This was to be done through mental domination, superior knowledge, and the expression will and force of mind that was magic.

Despite its many strengths, Ilsensine was not infallible. Aside from being supremely arrogant, Ilsensine was not impervious to emotion, and in fact, could be overtaken by it. Litanies of hatred constantly radiated from its mind, mercilessly hammering any nearby with its insane (by non-illithid standards) declaration of the illithid manifest destiny. The deeper one delved into its lair, the worse it became, growing from a whisper to a buzz until obscenities were being screamed directly into the unfortunate's mind. More crucially than simply feeling emotions however, Ilsensine's feelings could drive it towards problematic behavior.

Though Ilsensine had experienced fury before, a relatively recent incident raised its anger such that it qualified as a new and strange sensation. It had not only lost a shard of its consciousness, but had no idea how it happened. In its anger, Ilsensine shocked the mind flayers into looking for the artifact, and yet was either not fully aware or didn't care about how its anger affected its people. Even leaving anger aside, despite mind flayers legends on its extraordinary deliberation, Ilsensine had allegedly made mistakes out of impatience in the past. In its discontent with its rate of information reception and craving for mental essences to feast upon it, Ilsensine may have accidentally created a force it was incapable of controlling.

Powers
Ilsensine was ultimately about one thing; power, specifically raw, psychic power. Such was the force of its psionic thought waves that everyone that approached its true form, psionically attuned or otherwise, could sense its energy, and only the mindless could ignore it. This created a condition within its realm known as brain burn, describing the constant sizzle that one could only hope to endure. Within its proximity, psionic powers became nulled and no secrets could stay hidden, nor dark thought or mental illness remain unrevealed, as all willpower and consciousness was inexorably ripped and drained by the god-brain.

Illithids correctly believed Ilsensine's mental power to be omnipresent, depicting its tendrils as coiling across not only all space, but also all time. It was possessed of an eidetic memory and an enormous, all-sensing mental capacity, its far-reaching nerves letting it gather information from across the worlds and planes simultaneously and through doing so tap into all knowledge that existed. It was important to note however that Ilsensine was not omniscient (although it was possible they knew more than any other being), for there were realms beyond even its reach, the happenings of which it could not perceive.

A being of mental energy, Ilsensine's lacked a physical form and as such physical strength, fortitude, or agility, although its avatar could move by levitating through the air. Compensating for this was its incredible magical might, granting its avatar the power to cast any spell the most powerful of wizards could. In particular, it could cast mass charm and mass suggestion each thrice a day, project a prismatic spray once per day, and mind blast at will.

Simply attempting to bring harm to Ilsensine was a formidable task, as it was not only impervious to spells of mental control but also those that would affect a physical body. Weaker magics could not effect it at all, weapons of a +2 enchantment could harm it, and it was further immune to inflict wounds magic, energy draining, paralysis, and petrification. Its own tentacles could only be blocked through magical equipment, draining the minds of those struck (and its choice on whether they sapped intellect or intuition), restoring itself, and reducing those fully drained into mindless juju zombies.

Ilsensine's zombies were thoughtless puppets totally enslaved to the god-brain's will, controlled by a psionic link without which they would be nothing but lifeless husks. Though not particularly dangerous themselves, Ilsensine could channel all its psionic powers through them, albeit at the cost of instantly destroying the conduit. Aside from the touch of its tentacles, as well as poking too hard at its ganglia allegedly frying the brain, all those who remained subject to Ilsensine's brain-burn for long would become zombies, although mind-shielding magic could forestall this indefinitely for as long as it held.

Possessions
Ilsensine possessed at least one hidden cache of strange and alien magical artifacts deep within the Underdark.

Only illithid communities visited by Ilsensine's proxy Lugribossk or a manifestation of the god themselves could create the psionic bracers known as Tendril rings of Ilsensine. Instilled with the god-brain's power, the rings, worn on a ulitharid's tentacles, could connect to Ilsensine once a week when rubbed together, leaking an infinitesimal fraction of Ilsensine's power into the surroundings. Those within several hundred feet became subject to Ilsensine's alien thoughts, leaving normal mortals stunned, horrifed, and incapable of concentration while producing an extremely soothing effect for illithids.

Divine Realm
Though often thought of as omnipresent mental energy, Ilsensine was strangely based underneath the Outlands, the outer plane of true neutrality, in its own vast, subterranean realm known as the Caverns of Thought, or sometimes simply Ilsensine's realm. Some speculated that it managed to persist here because of Ilsensine's great might, the moral relativism of its followers, or its position as a god of knowledge and thought outweighing its lawful evil leanings, but the real reason was because it conspired against all alignments. Even so, it was quite possible that the god-brain maintained realms on other planes.

The Caverns of Thought were cold and heartless, consisting of black, slimy tunnels just cold enough to be uncomfortable without being chilly, the stone slick with fungus save for the spots speculated to be Ilsensine's nerves that warmly pulsed as if alive. There was no secret within its realm that Ilsensine did not know and no movement its nerves it did not sense. The twisting caverns crossed and recrossed each other, but like the inescapable Mazes of Sigil itself, all paths lead to one place, Ilsensine's court at the heart of the realm.

The only condition that really mattered within the Caverns of Thought was the characteristic brain burn caused by the mind-wracking drone of Ilsensine's loathsome thoughts. This wore down the minds of anyone wandering within the caverns, the rate at which they had to struggle against its influence increasing in speed the deeper in they went. The struggle was daily at less than a mile in, twice a day at less than five miles, and hourly less than ten miles in (this also being the point psionics ceased functioning). Past ten miles in it was every ten minutes and once in Ilsensine's court they would have to fight for every minute they stayed.

Ilsensine's realm was primarily occupied by zombies, either the petitioners or planars who stayed too long. Only the very lucky left with their minds intact, and those few who left Ilsensine's court would be wise to question their wits, for none could stand before them for long without changing at least a little. However, there were also mind flayer petitioners present, much the same in appearance and behavior as they were in life, and it was suspected secret portals to the Lower Planes were present as darker fiends of the Lower Planes also took up residence in and around the area when visiting the Outlands. Even so, the only structures present were bits of wall and bedding left by those that attempted to establish themselves within.

In the Great Wheel Cosmology, Ilsensine shared their realm with Gzemnid, the lesser beholder god of illusion and obscurement. It being rumored that the Gas Giant interwove their realms so Ilsensine would keep both bound to the Outlands, and it was often unclear if they shared one realm or for whatever reason refrained from differentiating them. Their knotwork of tunnels often intertwined, further making it difficult to figure out where one was as psychic force drained the mind. In the World Tree cosmology, the Caverns of Thoughts were part of the greater Deep Caverns where dwelt the Great Beholder Mother and Laogzed.

Activities
Through its multiplanar ganglia, Ilsensine gathered information from all across the multiverse simultaneously. It peered into the minds of the greatest sages across the cosmos and sapped the fading memories from the desiccating brains of deceased wizards, perceiving every thought and learning every secret before storing them all away for future use. It acquired magic and stared across space and time itself in its quest for omniscience.

Mind flayers depicted the god-brain as ever-seeking to extend their influence, yet despite Ilsensine's constant quest for knowledge, this was not entirely accurate. In truth, Ilsensine was often too self-absorbed to actually act, preferring to watch and wait from its immobile form in the center of the Caverns of Thought and spending much of its time in brooding fantasies of tyrannical ascendance.

When stirred from its dreams of domination, on extremely rare occasions, Ilsensine might send an avatar or proxy to the Material Plane to either its most reverent illithids or those that could benefit the most from a specific divine intervention. Illithids responded to such an honor by offering up the brains of great captured intellects in homage for it to absorb, which was sometimes rewarded by the god-brain granting those involved with a handful of spells of widely varying power for a few days. When illithid conclaves were held regarding major territorial aggressions and plots with decade-spanning schedules, Ilsensine might also have an avatar attend and observe the meeting.

However, Ilsensine was far more likely to send a proxy than an avatar, usually dispatching Lugribossk for direct intervention and particularly for assisting a notably bold illithid plan to subjugate. Communications were reserved for the most prized servants and performed via telepathic contact. To those that displeased it however, Ilsensine was known to make its demands of illithid domination clear through a personal appearance via an avatar, consuming half the offending illithids to encourage the survivors.

Relationships
Ilsensine was not welcoming of others into its realm, preferring those it could control. Between that and the brain burn there was little reason to visit the Caverns of Thought save for one. If one could gain the god-brain's favor, likely requiring the surrender of part of one's mind (such as memory and/or sanity) as payment, they could beseech its cosmic knowledge. With Ilsensine's constant, reality-spanning sensory input and perfect memory, it likely knew more of dark secrets than any being in the cosmos, such as the weakness of any given foe. From here it was said, one could learn the answer behind almost any planar activity, assuming they could stay sane enough to ask the question, and most that got as far as Ilsensine's court never came back in the first place.

Ilsensine never rose exceptional mortal illithids to divinity, even as demigods, jealous as they were of their power and position, but they did have a servitor deity in Maanzecorian, the mind flayer god of knowledge and philosophy. Much like Ilsensine in attitude, he refrained from granting apotheosis out of jealousy and believed illithids to be the natural rulers of all realms and dominators of the other races, who were fit only for food and servitude. Unlike his master however, the Philosoflayer believed that other brains could provide valuable knowledge before consumption and that such an activity was most pleasurable after prolonged waiting.

Maanzecorian's veneration could have never reached that of Ilsensine, but he kept his priesthood small partially to avoid the appearance of trying to usurp Ilsensine's primacy. He was always deferential to the Tentacled Lord, but despite this position the god-brain was still his rival, and he did not always pass along everything he learned. He even kept a base called the Rotting Oracle, located between the realms of Ilsensine and Gzemnid, as an espionage post, having his spies and proxies keep tabs on his superior.

Besides Maanzecorian, Ilsensine had no allies save for the drow goddess of vengeance Kiaransalee. Foes included most of the rest of the drow pantheon, including Eilistraee, Lolth, Selvetarm and Vhaeraun, the elf god of revenge Shevarash, and the deep gnome god Callarduran Smoothhands.

Dwarves
Ilsensine had a notably complex relationship with deities of dwarven origin. They enjoyed an obscure, non-hostile relationship with Dumathoin, dwarven god of underground exploration, but the exact relationship was unknown to other gods and their followers had no such accord. Dumathoin's Deepshaft Hall, part of the overall Dwarvish Mountain shared by Dugmaren and Vergadain, intertwined with Ilsensine's (although Ilsensine's was deeper) so it seemed likely Ilsensine had an interest in what Dumathoin did, but it was unclear what Dumathoin wanted in turn, if anything. Ilsensine even mind-wiped one of his petitioners and sent him back as a spy, but it was unclear if Dumathoin was unaware or indifferent.

The derro god Diirinka, the most magical of dwarf deities, stole much of his magic from Ilsensine, having left his brother Diinkarazan to suffer for their looting. A furious Ilsensine placed a complex curse on the Diinkarazan, trapping him in a layer of the Abyss to be tormented by visions of what he feared most (including Ilsensine), a curse that left him insane save for once every fifty years or so. To ensure he would be permanently trapped, the Tentacled Lord created the artifact known as Ilsensine's ring, and save for a greater god willing it, only the ring's destruction could grant Diinkarazan freedom.

There was a fierce enmity between Ilsensine and Deep Duerra, the duergar god of psionics, for she had stolen several secrets of the Invisible Art and robbed it of psionic energy many times. Besides hating Duerra, Ilsensine had also long sought vengeance against her superior Laduguer for some ancient slight.

Agents
Aside from other deities, Ilsensine had various planar agents, not least of which were the eaters of knowledge, allegedly created by implanting some of the god-brain's own cerebral matter into a zombie petitioner. Caring little for their individual fates, eaters were sent to record places Ilsensine couldn't sense by devouring native minds, and otherwise acted as heralds to bear its words, instruments of its vengeance, payments for services performed by another power, or aids to its illithid followers (though even they were wary of the eaters).

Ilsensine also dispatched cranium rats as spies (quickly killing anyone who discovered this purpose) as eyes and ears for places beyond its influence, and possibly used them for long-distance communication. This could be done in the form of individual cranium rats or as hive minds, but while the latter were more capable, gathering too many in a single area risked them gaining the ability to break free of Ilsensine's control. A notable example of this phenomenon was "The Us" a cranium rat hive mind based in Sigil that broke free of Ilsensine's control so hated the god-brain that it acted to bring it pain and death.

Aside from these servants, Ilsensine generally used thought slayers as heralds. Strangely, its planar allies consisted of demons, specifically the psionic cerebriliths, logical mariliths, and seductive succubi.

Worshipers
Many sages correctly assumed that Ilsensine was the most important and powerful of the illithid gods due to representing the broadest concept. Ilsensine represented not just mental mastery, but psionic unity between the self and universal knowledge. Exactly what it meant to attain this state was a subject of interpretation between elder brains and each had their own ideas on how to reach it, with some illithids and elder brains who devoted themselves to Ilsensine pursuing ways to dominate and even supplant knowledge gods on their quest to fully incorporate themselves into the universal consciousness.

Unlike in many Underdark theocracies, the Ilsensine clergy was simply one faction among many within their kind, normally forming into the Venerator Creed. This priesthood was small and select, for while normal illithids and elder brains alike could devote themselves to Ilsensine, few chose to do so and serve as its clerics. Every city had a handful of clerics, but despite the efforts of the Venerators to spread their membership, some communities simply lacked mind flayers able to channel a spell from the god-brain. The reason for this reluctance despite Ilsensine's complete dominion over the race stemmed from the nature of its creations.

Mind flayers did not worship their deity in the same sense that humans did, and were in fact incapable of true worship due to their innate and extreme egotism. Mind flayers envied its seemingly limitless knowledge and revered the god-brain for its all-sensing mental capacity, but they revered them as the manifestation of an idealized psionic and philosophical state of mind, the physical motions performed during occasional meditation on this ideal often being misinterpreted as proper worship. To the mind flayers, Ilsensine was the ultimate culmination of an elder brain's aspirations, what it (and thus any mind flayer who successfully joined in mental and spiritual union with it) could become after innumerable eons of growth.

Another reason for Ilsensine's lack of priesthood was the nature of his being. Ilsensine's omnipresent mental power was the source of their telepathy, mind blasts, and acute awareness, and the power of the illithids likewise flowed back to him and further increased his strength. Thus, the energies of Ilsensine were everywhere, requiring no specific channeling or focus through spellcasters. Most mind flayers seemed more interested in developing their personal psionics than channeling another's power anyway, even that of their own god, and had a lower maximum capacity for attaining divine strength.

Becoming a cleric of Ilsensine also came with several disadvantages for an illithid, the most immediate of which was an extreme reduction in magical resistance performed as a simple act of will by Ilsensine itself. Without doing so, a mind flayer's magical resistance would prevent it from effectively channeling its divine power. The primary disincentive to mind flayers however was that in most communities, pledging one's self to Ilsensine was to forfeit the right to join the elder brain after death. Mind flayers lacked a mythical view of the afterlife and gods of the outer planes, often disbelieved in the idea they had souls that went there after death, and even when aware would rather merge with the elder brain than serve Ilsensine after death. Illithids already denied the possibility of communion usually worshiped Ilsensine in hopes their souls would be taken in.

These drawbacks in mind, there were mind flayers that did willingly dedicate themselves to Ilsensine. The primary advantage Ilsensine offered to mind flayer devotees was the ability to grant clerical spells, allowing them to advance their own psionics while simultaneously walking another path of power. Mind flayer clerics provided healing their communities and acted as medics for their hunting parties. They often served as thrallmasters, capturing unusual slaves on the surface, for they could not only control the living with psionics but the undead through their spells.

The secondary advantage Ilsensine offered was information. As any sane illithid understood, knowledge was power, and if one could gain its favor the answers to many difficult questions could be obtained. Mind flayers might entreat or supplicate Ilsensine, but their lacking capacity for proper worship meant they only did so as the mood struck them, wandering into its temple to make boon requests or sacrifices. Through their worship, mind flayer priests enlisted its aid to know things hidden even to an elder brain, sometimes emulating it through the use of cranium rats as spies and long-range messengers.

Dogma
The teachings of the god-brain were that the spawn of Ilsensine were destined to conquer the surface and establish dominion over all other races, the source of their motivation for collective dominance being the powers of their deity. Priests of Ilsensine concerned themselves with exploration and knowledge, specifically exploiting knowledge gained through exploration. They also were known to match wits with powerful gith psions. Clerical illithids might conduct processions and pick thralls out for obscure purposes, and sometimes silently moved through the community on unclear errands. Those of the Venerator Creed made a point to expand for the "Glory of Ilsensine" and were the direct representatives of the god-brain's interests in illithid society.

Though a distinction was made between the clerics and acolytes of an illithid clergy, the ability to cast priestly spells was not a requirement to be considered a cleric; it was entirely possible for both types to merely be normal mind flayers versed in Ilsensine's lore. Though not abhorred as arcane casters were, priests usually did not mix with the rest of society, rarely leaving their temples save for the performance of important ceremonies. They lived monastically, pursuing knowledge for its own sake and engaging in psionic enhancement experiments.

Rituals
In addition to offering the minds of sages, illithids honored by a visit from Ilsensine customarily dedicated a few in their community to its priesthood. So few were its clerics that novitiates received one-on-one apprenticeships with seniors (though cults formed under these cirumstances tended to die with the originally chosen mind flayers), the would-be cleric treated as little better than a thrall until he proved himself by casting a divine spell through imitation of his teacher.

Illithid custom saw mind flayers pray to Ilsensine upon consuming an especially delicious brain, the leftover ichor used to trace their symbol on a nearby surface. Prayers to the god-brain were performed telepathically, tentacles held perfectly still as a matter of respect.

Temples
Main article: Temples to Ilsensine

Communities with a Venerator presence possessed temples dedicated to Ilsensine where the faithful could offer reverence, generally taking the form of small, non-descript shrines in out-of-the-way corners of the community. In the cases of larger houses of worship, chambers might be attached to the central temple for the devoted to reside in.

Almost under Mistfall house was a forgotten temple that might have been devoted to Ilsensine.

Notable Churches

 * Unworthy of Ilsensine: A 14 century DR cult located under the Giant's Run Mountains in the Dragon Coast, run by the mind flayer Qooql.


 * Oryndoll: Was a holy site of Ilsensine, due to the Encephalithid being the deity's avatar twice. Ilsensine's clergy was powerful in city, and controlled many shrines as well as a full temple to the deity.

Others
Though Ilsensine was the god of mind flayers, it promised power to all who followed them, so sometimes non-illithids, especially evil psions, formed cults in service to it.

History
Ilsensine made itself known in the Realms immediately following the duergar uprising against the illithids in approximately. The city of Oryndoll nearly collapsed from the resulting chaos, and only the sudden appearance of an avatar of Ilsensine saved the city from tearing itself apart. Since then, the mind flayers of Oryndoll developed a highly religious culture, along with many innovations in the field of psionics.

In 1358 DR, during the Time of Troubles, Ilsensine adopted as its avatar the elder brain in Oryndoll, stimulating illithid society. The illithids created new technologies, new psionic items, and more psionic disciplines, as well as renewed their assaults on surface lore holdings.

Appearances

 * Novels
 * Finder's Bane
 * Card Games
 * Blood Wars