Energon, Xeg-Yi
DESCRIPTION: The xeg-yi is a dark energon which embodies the pure soul-sapping void energy of the Negative Energy Plane. It is a floating, globular knot of shadowy force that radiates spirit-leeching cold, ultraviolet luminance. It is surrounded by a palpable hush—as if sound itself were being unmade—while nearby metals pit and wood fibres rot and crumble under its passing. Encountering a xeg-yi feels like being plunged into a vacuum: Your breath shortens, colours dull, and your thoughts skid on an alien static. Psychic probes risk a stunning feedback, and the air smells faintly of bleach and dust. Motes drift toward the orb and wither on contact. Up close, the surface of a xeg-yi seethes with dozens of slowly-moving tendrils of null-light that leave stains of necrotic rime wherever they graze. The faint corona of un-light marks walls and stone with subtle, negative afterimages that seem to lag in time.
Dustmen treat xeg-yi with hushed reverence, as exemplars of the True Death’s quiet, sometimes hiring them as dispassionate escorts through dead-magic ruins. Bleakers read their apathy as proof of a purposeless multiverse, while the Sensates find them maddeningly indifferent to meaning or sensation—although touching a xeg-yi is something of a rite of passage for a self-respecting Sensate. Xeg-yi oppose or ignore most undead unless their mysterious goals demand otherwise, but necromancers and liches have been known to court their favour. Scholars of the Fraternity of Order compare them with xag-ya as paired studies in balance.
PREFERRED HABITAT: Xeg-yi are natives of the Void of Negative Energy, where they drift through anti-life gradients and deathly rifts, immune to the plane’s oppressive drain. In the Negative, xeg-yi are both buoyed and camouflaged by the entropic flux that strips vitality from mortals in moments. When ranging beyond their home, they are most at ease in dark, magic-dulled locales—dead-magic zones, shadowy crypt vaults, necromantic laboratories, and ancient ruins steeped in entropy. They are drawn to places where the Weave frays and living auras are thin. Off-plane, xeg-yi act as curious wayfarers or even coldly pragmatic guides when properly approached, leading caravans through perilous zones in return for offerings of unusual inert matter to “taste” and study as it decays.
PHILOSOPHY / SOCIETY: Xeg-yi are largely solitary, because their very presence corrodes tools, spoils environments, and destabilizes the energies other beings require. They even seem to avoid their own kind. Accounts from planewalkers suggest they have a detached, investigative temperament: xeg-yi are intrigued by processes of ending—rust, rot, silence, stillness—and can even exhibit a disciplined control of their negative lash to avoid healing undead foes, implying self-restraint and preference rather than blind hunger. Their philosophy, insofar as cutters have parsed it, treats negation as refinement: Removing the noise of substance reveals form. They prune away excess until only essence remains, with no cruelty, just detached calm.
ECOLOGY: It’s thought that xeg-yi to feed upon the entropy flux of the planes—materials visibly crumble to dust around them. Xeg-yi have never been known to reproduce, in fact, they don’t even seem to interact with one another. Void energons of different sizes have been encountered, so graybeards believe they do age and grow, and presumably reproduce asexually.
Xag-ya and xeg-yi are opposite aspects of planar energy; if two should ever they meet, they rush together and annihilate in an amplified explosion. It’s a phenomenon that daring planewalkers have exploited as a dangerous, last-resort planar flare or as a ritual reset to cleanse cursed areas.
COMBAT: In combat, a xeg-yi will strike with its tendrils or shoot entropic void-energy rays at a range. They cause solid objects to crumble, rusts metals, and withers plants. The void energy of a xeg-yi can heal undead, if the xeg-yi wishes, as mature energons are able to modify the void energy to boost the unliving, or to distintegrate their bodies, damaging them.
Xeg-yi use their incorporeality to gain a tactical advantage, ducking into walls and ceilings. They leave rot marks on solid objects when they do this, making tracking easier. Magical weapons are required to damage a xeg-yi. Upon destruction, a xeg-yi detonates in a concussive surge of necrotic energy that can also disintegrate non-magical cloth, wood or metal.
Sources
Full Statistics: [ D&D 2e | 3e / PF1e ]
Canonical Source: Manual of the Planes [1e] p54, [3e] p168-169, [5e] p412; Planescape Monstrous Compendium Vol. III [2e] p118
Source: Margarita and Jon Winter-Holt
