Actions

Multiattack. The Viscerleech makes two Drain Life attacks.

Drain Life. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 6 (1d6 + 3) Necrotic damage and the creature is Grappled by the Viscerleech (escape DC 12). The Viscerleech regains Hit Points equal to half the damage it deals. The Viscerleech can only have one creature Grappled at a time. A Viscerleech automatically ends this Grapple upon entering a creature via Invade and Bond.

Invade and Bond. The Viscerleech targets a living, Medium-sized or larger creature that it has Grappled. If the creature is unwilling, it must make a DC 12 Constitution saving throw. Failure: The Viscerleech enters the creature's body and bonds to it, becoming able to use the reactions listed in this statblock.

Forceful Excretion. The Viscerleech exits its current host creature and appears in an unoccupied space of its choice within 5 feet of that creature. The host takes 1d2 damage in the process (no save).

Reactions

Mutualism. When the Viscerleech's current host takes damage, the Viscerleech can choose to invigorate it, allowing the host to expend a Hit Die to heal. The host expends one Hit Die and rolls it, healing for the result + its Constitution modifier. If all the host's Hit Dice have been expended, the Viscerleech can heal the host by 5 (1d6 + 2) Hit Points, subtracting the amount healed from the Viscerleech's Hit Points.

Parasitism. When the Viscerleech's current host takes damage, the Viscerleech can choose to damage the host's internals. The host must expend a Hit Die and roll it. Instead of regaining hit points, the host takes damage equal to the number rolled minus its Constitution modifier. If all the host's Hit Dice have been expended, the Viscerleech can damage it by 5 (1d6 + 2) Hit Points, subtracting the amount dealt from the Viscerleech's Hit Points. In either case, damage taken by the host in this manner bypasses resistances or other forms of damage reduction.

Motivation/Compulsion

A Viscerleech's existence revolves around a phenomenon it calls “feast.” Although the word sometimes refers simply to feeding, to a Viscerleech it describes something considerably broader: the sensation produced by a Viscerleech exposed to living tissue under stress, injury, decay, and death. Pain, fear, blood, rot, and the gradual failure of a living body are all components of feast, experienced by the creature as nourishment, pleasure, and meaning simultaneously.

A Viscerleech therefore does not pursue food in the conventional sense. It seeks situations in which suffering and decay can be experienced at close range and, ideally, sustained for as long as possible. A fresh corpse may satisfy its hunger, but a wounded creature that continues to struggle is considerably more desirable. Likewise, a battlefield is valuable not merely because it contains corpses, but because it provides an environment in which injury, death, and decomposition occur together.

This fixation is powerful but not entirely mindless. A Viscerleech understands that it must survive to experience further feast, and will ordinarily retreat from danger when doing so would preserve its future opportunities. However, particularly intense or unusual sources of feast can overcome this caution. A Viscerleech may remain attached to a dying host despite obvious danger, abandon a secure position to pursue the sounds or sensations of nearby violence, or willingly accept an otherwise unfavorable bargain if it promises prolonged access to feast.

Viscerleeches are consequently capable of cooperation without being particularly altruistic. A creature that offers a safe host, protection, or access to a reliable source of suffering may find a Viscerleech surprisingly compliant. Such arrangements can even become long-term associations, provided the Viscerleech continues to receive what it considers a satisfactory feast. It has little concept of morality, however, and may violate an agreement without hesitation if doing so presents an opportunity for a significantly greater one.

This also means that a Viscerleech does not understand suffering as a negative experience. Pain, fear, weakness, and the gradual deterioration of the body are, to it, sensations no different in principle from warmth, pressure, or taste. It recognizes that other creatures attempt to avoid such sensations, and can understand that injury causes distress, but it has little capacity to comprehend why suffering should be undesirable. To a Viscerleech, pain is simply information, and intense pain is particularly meaningful information.

This distinction makes the creature's behavior difficult for other sentient beings to understand. A Viscerleech may deliberately preserve an injured host rather than allow it to die, not out of compassion, but because continued suffering produces a richer and more sustained feast. It may even attempt to prevent a creature from escaping, healing, or dying too quickly, regarding each as an interruption of a valuable experience. When confronted with an offer to end another creature's suffering, a Viscerleech may react with genuine confusion as to why would anyone willingly discard such a profound sensation.

The Viscerleech's greatest danger is therefore not some unquenchable hunger, but its inability to regard suffering as anything other than desirable. Where another creature sees a battlefield, a dying animal, or a rotting corpse, the Viscerleech sees an opportunity. The stronger the promise of feast, the more difficult it becomes for the creature to consider anything else.

Usual Tactics

In battle, a Viscerleech avoids direct confrontation whenever possible. When allied with a creature, a Viscerleech uses its anatomy defensively, reinforcing the host and absorbing harm on its behalf. While embedded, it remains focused on preservation rather than offense, reacting to threats by tightening its coils and mitigating damage rather than retaliating directly.

Against an enemy, however, it has no such restraint: it enters aggressively and turns the host's own body into a weapon. Within a hostile creature, a Viscerleech will actively sabotage and drain the vitality of their unwilling host in combat, tightening around organs and damaging other internals. Should the foe perish, a Viscerleech will burst out from their remains just as violently as they entered, seeking out either an ally as a willing host, or another foe to feed off of.

When sufficiently wounded or forced to act independently, a Viscerleech exits its current host and disengages briefly to drain vitality from nearby enemies, leeching from them to repair its own injuries before seeking another host. It prefers drawn-out engagements where suffering accumulates over time, and will retreat or reposition if combat becomes too swift or overwhelming. A Viscerleech rarely fights to the death unless escape would deny it access to an extremely strong source of its coveted 'feast', in which case it may cling to a host until forcibly removed.

Suggested Environments

Viscerleeches favor environments that provide enclosure, warmth, and a steady presence of decay or suffering. They are rarely found on or above the surface, favoring underground cave networks or large caverns. They are most commonly found in places where death is frequent but not final: battlefields left to rot, plague-stricken settlements, mass graves, and monster-infested ruins where corpses accumulate faster than they are cleared. Underground spaces such as crypts, sewers, and collapsed tunnels are especially attractive, as they offer both confinement and rich organic residue.

In living environments, Viscerleeches often linger near predators, warbands, or violent cults, attaching themselves to hosts who are likely to experience injury or prolonged conflict. They show little interest in pristine or well-maintained areas unless such places conceal hidden sources of decay, such as sealed tombs or suppressed outbreaks. Open wilderness and high-altitude regions are typically avoided and even feared unless a reliable host is available.