Symbionts

Symbionts are not complete monsters in themselves. Rather, they are sentient beings that merge with existing creatures to enhance them. Symbionts have minds of their own and attach to their hosts in a variety of ways.

Symbionts are generally capable of surviving apart from a host creature for at least some length of time. They are generally Tiny or smaller, and physically very weak on their own. They survive by joining with a host creature, usually granting the host certain benefits in exchange for the protection afforded by a larger body. This symbiotic relationship usually benefits both parties (though in some cases the symbiont might better be described as a parasite).

A symbiont occupies part of the host creature’s body⁠—​sometimes, but not always, limiting the number of magic items the host can use in the same way as a magic item does. Like intelligent magic items, symbionts have Ego scores, which reflect their strength of will and drive for power. Symbionts with high Ego scores, like such magic items, can sometimes take control oftheir host creatures.

The Ego score of a symbiont is determined in the same way as that of an intelligent magic item, and listed with each symbiont’s entry. Add the symbiont’s Intelligence, Wisdom, and Charisma bonuses (if any) to determine its base Ego score. Add 1 for each special quality and 2 for each special attack. Add 4 if the symbiont is an outsider.

For example, a fiendish familiar has a base Ego score of 1 (from its 12 Intelligence), plus 1 for its arcane education special quality, 1 for its enhance spellcaster special quality, 1 for its telepathic ability, and 4 for being an outsider, for a total Ego of 8. Evil and malevolent asa fiendish familiar may be, few characters stand any risk of having it subvert their will. On the other hand, a mind leech has a base Ego score of 8 (Int 16, Wis 14, Cha 16), plus 2 for its mind blast special attack, 4 for its psionic abilities of charm monster and suggestion, 1 for its detect thoughts psionic ability, and 1 for its telepathy, for a total Ego of 16.

If the host creature does not share the symbiont’s alignment and goals, a conflict results between the symbiont and the host creature. Similarly, a symbiont with an Ego score of 20 or higher always considers itself superior to its host, and a personality conflict results if the host does not always agree with the symbiont.

When a personality conflict occurs, the host must make a Will saving throw (DC = symbiont’s Ego). If the host creature succeeds, it is dominant. If the host fails, the symbiont is dominant. Dominance lasts for one day or until a critical situation occurs (such as a major battle, a serious threat to either the symbiont or the host, and so on⁠—​DM’s discretion). Should a symbiont gain dominance, it directly controls the host creature’s actions until the host regains dominance.

Symbiont Traits: When joined with a host, a symbiont gains a number of benefits. It acts on its host’s turn each round, regardless of its own initiative modifier. It is not flat-footed unless its host is, and it is aware of any danger its host is aware of.

If a symbiont is grafted onto a visible part of the host creature’s body (as opposed to the mind leech, for example, which coils around the host’s brain stem), opponents can attack the symbiont itself instead of its host creature. This works the same way as attacking an object: The symbiont gains the benefit of the host’s Dexterity modifier to AC instead of its own, and gains any deflection bonus to AC the host has as well. Its own size modifier and natural armor bonus, if any, apply. Attacking a symbiont instead of its host provokes an attack of opportunity from the host.

A symbiont never takes damage from attacks directed at the host. Like a worn magic item, a symbiont is usually unaffected by spells that damage the host, but if the host rolls a 1 on its saving throw, the symbiont is one of the “items” that can be affected by the spell (see Items Surviving after a Saving Throw). A symbiont uses its host’s base saving throw bonuses if they are better than its own.

Share Spells (Su): Any spell the host creature casts on itself automatically also affects the symbiont. Additionally, the host may cast a spell with a target of “You” on the symbiont instead of on itself. Likewise, a symbiont can choose to have any spell or spell-like ability it uses on itself also affect the host creature, and may cast a spell with a target of “You” on its host instead of on itself. The host and symbiont can share spells even if the spells normally do not affect creatures of the host or symbiont’s type. Spells targeted on the host by another spellcaster do not affect the symbiont, and vice versa.

Cerebral Symbionts

Cerebral symbionts have in common some assortment of psionic powers and, at least in theory, some connection to the mind flayers, who are presumed to have created them.

Combat

Cerebral symbionts are not generally powerful combatants on their own merits. The cerebral hood is an exception, because its method of attachment requires overpowering its host.

The statistics block below contains details for more than one type of cerebral symbiont. Use the horizontal scrollbar below it to display the desired one or select from the links below that.

Cerebral Hood • Mind Leech • Psionic Sinew

Cerebral Hood ⬆️

The cerebral hood resembles a small cloaker, though it has no eyes or mouth, It is a black, somewhat amorphous, leathery creature that flies slowly by undulating its body through the air. A long tail dangles from its mass, thick and heavy but also wet and tubular, Numerous spiny protrusions extend from the tail.

Cerebral hoods do not speak any language, but they understand Undercommon.

Combat

A cerebral hood attaches itself to a host by engulfing the creature’s head and extending its tail into the creature’s mouth and down its throat. In the throat, the tail’s spiny tendrils extend to make key connections to the host body’s nervous, digestive, and circulatory systems. Because it is so weak, it prefers to attack stunned or helpless beings, so it often initiates combat with its mind blast or lingers near mind flayer lairs and waits for a victim of the illithids’ mind blast.

Engulf (Ex): A cerebral hood can try to wrap the head of a Medium-size or smaller creature in its body as a standard action. The hood attempts a grapple that does not provoke an attack of opportunity. If it gets a hold (grapple bonus −11), the target is effectively blinded and cannot breathe. The cerebral hood immediately begins trying to insert its tail into the victims throat, which requires another successful grapple check.

Because its grapple bonus is so poor, a cerebral hood generally attacks only stunned opponents in this manner.

Mind Blast (Su): This attack is a 60-foot cone. Anyone caught in this cone must succeed on a Will save (DC 17) or be stunned for 1d4 rounds. Each time the cerebral hood uses this ability, it deals 1 point of Intelligence damage to the host.

A cerebral hood without a host has a weaker mind blast. The cone is only 15 feet long, the save DC is only 13, and targets who fail their saves are stunned for only 1 round.

Mind Feeding (Su): A cerebral hood survives by consuming its host’s mental energy. This deals 1 point of Intelligence damage each day the hood remains attached. Ordinarily, the host regains 1 lost point of Intelligence each night, just before the cerebral hood drains a new point, keeping the host at an equilibrium point of −1 to its base Intelligence. When the cerebral hood uses its mind blast, however, it deals extra Intelligence damage, so overuse of that special attack can eventually destroy the host’s mind.

Blindsight (Ex): A cerebral hood is blind, but its entire body is a primitive sensory organ that can ascertain prey by scent and vibration. This ability enables it to discern objects and creatures within 60 feet. The cerebral hood usually does not need to make Spot or Listen checks to notice creatures within range of its blindsight. A cerebral hood attached to a host shares its sensory input with the host, conferring blindsight on the host.

Mouth Tube (Ex): A cerebral hood joins its host by extending its tail through the creature’s mouth and down its throat. The host no longer needs to eat or breathe, since the cerebral hood supplies it with oxygen and nutrients through a tube in its tail. The host is immune to gases, including inhaled diseases and poisons, and is not at risk from starvation or dehydration as long as it has Intelligence for the cerebral hood to feed upon.

Skills: A cerebral hood has a +4 racial bonus on Move Silently checks.

Source: Fiend Folio, page 216. Changes applied as per the D&D^® v.3.5 Accessory Update.

Mind Leech ⬆️

A mind leech is a small, slimy creature that coils itself around the brain stem of the creature carrying it. A mind leech’s host creature can gain no benefit from a magic amulet, brooch, medallion, necklace, periapt, or scarab.

A mind leech does not speak any language, but it understands Undercommon.

Combat

A mind leech is almost totally helpless when not attached to a host. It hides in wet areas and attacks creatures that pass through its space, using surprise to avoid attacks of opportunity.

Attach (Ex): If a mind leech hits with its bite attack, it burrows into the target’s flesh and makes its way to the brain stem. Since the bite deals no damage and the leech secretes an anesthetic, the host is often unaware it has been bitten until the mind leech has established itself at the seat of the host’s central nervous system.

Mind Blast (Su): This attack is a 60-foot cone. Anyone caught in this cone must make a Will save (DC 17) or be stunned for 1d4 rounds. Each time the mind leech uses this ability, it deals 1 point of Intelligence damage to the host. A mind leech without a host cannot use this ability.

Psionics (Sp): At will⁠—​charm monster, detect thoughts, dominate person, and suggestion. These abilities are as the spells cast by a 10th-level sorcerer (save DC 13 + spell level). Each time the mind leech uses its charm monster or suggestion powers, it deals 1 point of Intelligence damage to the host. Using its dominate person ability deals 2 points of Intelligence damage. A mind leech without a host cannot use these abilities (though it can detect thoughts).

Telepathy (Su): A mind leech can communicate telepathically with its host, if its host has a language.

Skills: A mind leech has a +4 racial bonus on Move Silently checks.

Source: Fiend Folio, page 217. Changes applied as per the D&D^® v.3.5 Accessory Update.

Psionic Sinew ⬆️

A psionic sinew is a revolting, wormlike length of muscle endowed with sentience and psionic power.

A psionic sinew does not speak any language, but it understands Undercommon.

Combat

A psionic sinew has no way to attach itself to an unwilling host. In general, creatures seek out a psionic sinew to gain its benefits (much like a graft), or encounter a psionic sinew and voluntarily attach it to their own bodies.

Claws of the Bear (Sp): At will (and usually at the host creature’s command), a psionic sinew can use the claws of the bear psionic power on the host. The host’s forearms lengthen and its hands (or equivalent appendages) broaden into wide paws with sicklelike bear claws. This power gives the host natural weapons that deal 1d12 points of slashing damage (plus the host’s Strength modifier) on a successful attack. The claws remain for 3 hours. Each time the psionic sinew uses this ability, it deals 1 point of Dexterity damage to the host. A psionic sinew without a host cannot use this ability.

Blindsight (Ex): A psionic sinew is blind, but its entire body is a primitive sensory organ that can ascertain prey by scent and vibration. This ability enables it to discern objects and creatures within 60 feet. A psionic sinew usually does not need to make Spot or Listen checks to notice creatures within range of its blindsight.

Enhance Strength (Su): A psionic sinew grants its host a +4 enhancement bonus to its Strength score. This bonus remains in effect as long as the psionic sinew is attached.

Inertial Armor (Su): A psionic sinew is surrounded by a tangible field of psychokinetic force that grants it a +4 armor bonus to AC. When attached to a host, the psionic sinew extends this field of force to cover the host creature as well. Inertial armor entails no armor check penalty, speed reduction, or arcane spell failure chance. Because it is composed of force, incorporeal creatures can’t bypass it the way they do normal armor.

Vigor (Sp): Once per hour, a psionic sinew can give itself or its host 3 temporary hit points that last for 1 minute. Each time the psionic sinew uses this ability, it deals 1 point of Dexterity damage to the host. A psionic sinew without a host cannot use this ability.

Source: Fiend Folio, page 218. Changes applied as per the D&D^® v.3.5 Accessory Update.

Fiendish Symbionts

Fiendish symbionts are among the most loathsome creatures in all existence⁠—​tiny spawn of the Lower Planes that survive only by attaching themselves to larger creatures.

Combat

As a rule, fiendish symbionts have no attack forms worth noting; only the soul tick is an exception.

Telepathy (Su): A fiendish symbiont can communicate telepathically with its host creature, if the host has a language.

Acquiring a Fiendish Symbiont

As with fiendish grafts, fiendish symbionts can be acquired by a variety of means. The same magical devices that attach fiendish grafts have also been known to attach fiendish familiars. Any kind of fiendish symbiont can be “given” to a character as part of a ritual or a reward from a fiend of corruption.

The gutworm and the soul tick also attach themselves to hosts in the same ways as more mundane parasites. The larval form of the gutworm often infests impure water, while the soul tick attaches itself to a host after making a successful melee attack.

Drawbacks of Fiendish Symbionts

Creatures of good alignment with a fiendish symbiont must make a Will save (DC 15) every day or take 1d3 points of Wisdom damage as the experience drives them slowly mad.

Creatures of a nonevil alignment must make a Will save (DC 15) each day or succumb to temptation to perform an evil act. This may result in an alignment change, eventually.

When characters with fiendish symbionts interact with nonevil NPCs, a −6 circumstance penalty is applied on all Charisma-based checks (Diplomacy, Bluff, and so on). This penalty applies even if the NPC is unaware of the symbiont’s presence, since it reflects the subtle twisting ofthe host’s personality.

Fiendish symbionts tend slightly toward parasitism, siphoning some of their host’s physical or spiritual strength. See the individual entries for details.

The statistics block below contains details for more than one type of findish symbiont. Use the horizontal scrollbar below it to display the desired one or select from the links below that.

Fiendish Familiar • Gutworm • Soul Tick

Fiendish Familiar ⬆️

A fiendish familiar is a small face with an evil expression that is grafted onto the shoulder, back, stomach, or hand of a character. It gives the most benefit to hosts who are arcane spellcasters.

Fiendish familiars speak Common and Abyssal, and can communicate telepathically.

Combat

Fiendish familiars do not engage in combat, nor do they specifically aid their hosts in combat⁠—​although the enhancements they offer to spellcasting hosts can be significant in such situations.

Arcane Education (Ex): When grafted to a wizard, a fiendish familiar can teach the character one new spell of each spell level the character can cast. Each time the character gains access to a new spell level, the familiar teaches the character one new spell in addition to the two spells the character automatically gains for advancing a level. When grafted to a sorcerer or bard, a fiendish familiar can serve as a source of spell knowledge as described in Learning New Spells.

Enhance Spellcaster (Ex): When grafted onto the body of any spellcaster, a fiendish familiar increases the character’s effective spellcasting-related ability score by 2 for purposes of determining bonus spells. If the character has more than one spellcasting class, each relevant ability score is improved in this way.

Source: Fiend Folio, page 219. Changes applied as per the D&D^® v.3.5 Accessory Update.

Gutworm ⬆️

An Abyssal relative of the tapeworm, the gutworm is a vile fiend that lives in its host’s digestive system. It appears as a 1-to-2-foot long segmented worm of deep purple color, dripping with thick yellowish slime. It has bulbous red eyes and a toothy maw. Unlike a tapeworm, it does not attach itself to the intestinal wall, but swims freely around within the digestive tract, creating an uncomfortable sensation in the host.

Gutworms do not speak, but they understand Abyssal.

Combat

Gutworms do not engage in combat.

Enhance Constitution (Ex): A creature with a gutworm symbiont gains a +2 inherent bonus to its Constitution score.

Incite Rage (Ex): At will, a gutworm can cause its host creature to enter a frenzied state identical to a barbarian’s rage (+4 Strength, +4 Constitution, +2 morale bonus on Will saves, −2 AC penalty). The rage lasts 4 rounds, and the host is not fatigued afterward.

Infect (Ex): Gutworm eggs are often found in the polluted water of the Abyss and infect creatures that drink the water. A purify food and drink spell does not remove the eggs from the water, although they die if left in pure water for one day. Once inside a host, the eggs hatch in 1d4 hours, and the spawn set about devouring one another until only one remains.

A remove disease spell cast on the host kills a gutworm, but the host takes 4d6 points of damage from the creature’s death throes.

A creature with a gutworm must eat twice as much food as it normally requires each day, and must start making daily Constitution checks after only one day without food (instead of the normal three days). In addition, the host creature is fatigued after 8 hours of activity and takes a −4 penalty on the following checks and saves: Swim checks to resist nonlethal damage; Constitution checks to continue running, to avoid nonlethal damage from a forced march, to hold its breath, or to avoid nonlethal damage from starvation or thirst; and Fortitude saves to avoid nonlethal damage from hot or cold environments, or to resist damage from oxygen deprivation.

Neutralize Poison (Su): Once per day, a gutworm can negate any poison introduced into its host’s body (not just ingested poisons), protecting its host from any ill effects.

Source: Fiend Folio, page 220. Changes applied as per the D&D^® v.3.5 Accessory Update. Changed purify water to purify food and drink.

Soul Tick ⬆️

The soul tick is an infernal arachnid that attaches itself to a host’s skin and feeds on its blood. Its body is about 1 inch in diameter, swelling to 2 inches when full of blood (or up to about 4 inches when it overfeeds). It is covered with a thin chitinous shell ofadark reddish-brown color, shading to bright red at the ends of its legs and its complex mouth. When attached to its host, its legs and head burrow into the host’s flesh, leaving just its body visible.

Soul ticks do not speak, but they understand Infernal.

Combat

Unlike other fiendish symbionts, soul ticks can make melee attacks. The creature’s preferred method of attack, however, is to hide in whatever terrain is available and attack creatures that pass through its space, using surprise to avoid attacks of opportunity. Once attached, it uses telepathy to communicate with its new host, trying to persuade it not to remove the tick and explaining its powers.

Attach (Ex): If a soul tick hits with its bite attack, it uses its mouth and eight legs to burrow into the target’s flesh, latching firmly onto the opponent’s body. An attached soul tick loses its Dexterity bonus to AC, making its AC 18.

Blood Drain (Ex): A soul tick drains blood, dealing 1 point of Constitution damage each day it remains attached, Ordinarily, the host regains 1 lost Constitution point each night, just before the soul tick drains 1 new point, keeping the host at an equilibrium point of −1 to its normal Constitution. However, once per day as a full-round action the soul tick can overfeed, draining enough blood to deal 1d4 points of Constitution damage to its host, usually as punishment for displeasing it.

Enhance Magic (Ex): Any spells with the death or evil descriptor, as well as spells that use negative energy in any way, are enhanced when cast by the soul tick’s host. Such spells are automatically empowered without changing the spell slot required or casting time.

Impede Magic (Ex): Any spells with the chaos or good descriptor, as well as spells that use positive energy in any way, are impeded when cast by the soul tick’s host. The host must make a Spellcraft check (DC 15 + spell level) when trying to cast such a spell. If this check fails, the spell does not function and is lost. If the check succeeds, the spell functions normally.

Protective Aura (Su): A protection from good or protection from chaos effect constantly wards a soul tick and its host, as the appropriate spell cast by a 12th-level sorcerer. The soul tick can can create it again during its next turn as a free action. The defensive benefits from the aura are not included in the creature’s statistics.

Vulnerable to Holy Power (Ex): A soul tick’s host is affected by holy power (such as holy smite spells and weapons with the holy property) as if the creature were evil, regardless of its actual alignment.

Source: Fiend Folio, page 220. Changes applied as per the D&D^® v.3.5 Accessory Update.

Undead Symbionts

Ghostly Visage

A minor undead spirit similar to a ghost, a ghostly visage inhabits corporeal bodies. Its name comes from its ability to manifest a transparent face on its host’s body.

When not attached to a host, a ghostly visage looks like little more than a puff ofsmoke about 1 foot in diameter. Only by looking carefully can a character discern its eyes, which appear simply as dark spots within the smoke. When attached to a host, the visage normally lurks inside the host’s body. It can, however, manifest a face on the host’s body, including covering the host’s own face. This face has a horrible appearance, contorted in the agony of undeath.

Ghostly visages speak Common and any one additional language.

Combat

Ghostly visages avoid open conflict, instead trying to incorporate themselves into a host through stealth.

Because a ghostly visage is automatically affected by spells its host casts on itself, it rarely chooses to join a character capable of casting healing spells or similar spells that would damage it while benefiting the host.

Gaze of Terror (Su): Anyone within 30 feet of a ghostly visage who meets the eyes of its manifested face (see visage below) must make a Will saving throw (DC 13) or be paralyzed with fear for 1d4 rounds. Ghostly visages are immune to their own gaze attacks and to those of others of their kind.

Meld (Su): Once per round, a ghostly visage can merge its body with a corporeal creature. If it makes a successful incorporeal touch attack, the ghostly visages body disappears into the opponent’s body. The target can resist the attack with a successful Will save (DC 13). A creature that successfully saves is immune to that ghostly visages meld for one day.

Visage (Ex): At will, a ghostly visage can manifest a face anywhere on its host’s body, including over the host’s own face (the host’s vision is unaffected). This face looks corporeal and fleshy, but it is actually the visage’s incorporeal form. When manifesting a visage, the ghostly visage is susceptible to attacks separate from its host. Attacks that miss the visage because of its incorporeal nature (including attacks from nonmagic weapons as well as attacks that are foiled by the 50% chance to ignore damage) target the host instead. For attacks that require attack rolls, ifthe attack roll exceeds the AC ofthe host, the host takes damage instead of the visage.

Mind Shielding (Ex): When attached to a host, a ghostly visage protects the host from mind-affecting spells and effects. This ability is similar to a mind blank spell, but does not protect the creature from divination spells that are not mind-affecting. In essence, the ghostly visage confers its undead immunity to mind-affecting spells upon the host.

Skills: A ghostly visage has a +4 racial bonus on Bluff and Intimidate checks.

Source: Fiend Folio, page 221. Changes applied as per the D&D^® v.3.5 Accessory Update.