b'Nihilith \n'b'  Family:   Aboleth  \n'b'  Large   undead ,  chaotic evil  \n'b'  Armor Class  17 (natural armor)  Hit Points  135 (18d10 + 36)  Speed  10 ft., swim 40 ft., fly 40 ft. (ethereal only)\n'b' STATS STR: 21 (+5) DEX:  9 (\xe2\x80\x921)  CON:  15 (+2)  INT:  18 (+4)  WIS:  15 (+2)  CHA:  18 (+4)  \n'b'\n'b'\n'b'\n'b'\n'b'\n'b'\n'b'  Saving Throws   Con  +6,  Int  +8,  Wis  +6  Skills   History  +12,  Perception  +10  Damage Resistances  acid, fire, lightning, thunder (only when in ethereal form); bludgeoning, piercing and slashing from nonmagical weapons  Damage Immunities  cold, necrotic, poison; bludgeoning, piercing and slashing from nonmagical weapons (only when in ethereal form)  Condition Immunities   charmed ,  exhaustion ,  frightened ,  grappled ,  paralyzed ,  petrified ,  poisoned ,  prone ,  restrained   Senses   darkvision  120 ft., passive Perception 20  Languages  Void Speech, telepathy 120 ft.  Challenge  12 (8,400 XP) \n'b' Special Traits \n'b'\n'b'  Aboleth Traits . Unless noted otherwise or where contradicted below, a nihileth has the same traits as a living aboleth. This includes legendary  actions  and lair  actions . \n'b'  Undead Nature . A nihileth does not require air, food, drink, or sleep. \n'b'  Undead Fortitude . If non-radiant damage reduces a nihileth to  0 hit points , it makes a  Constitution  saving throw with a DC of 5+ the damage taken. If it succeeds, the nihileth drops to 1 hit point instead. \n'b'  Dual State . A nihileth exists upon the Material Plane in one of two forms and can switch between them at will. In its material form, it has  resistance  to damage from nonmagical weapons. In its ethereal form, it is immune to damage from nonmagical weapons. The creature\xe2\x80\x99s ethereal form appears as a dark purple outline of its material form, with a blackish-purple haze within. A nihileth in ethereal form can move through air as though it were water, with a  fly  speed of 40 feet. \n'b'  Void Aura . A nihileth doesn\xe2\x80\x99t secrete the mucous cloud of an aboleth. Instead, the undead nihileth is surrounded by a chilling cloud. A living creature that starts its turn within 5 feet of a nihileth must make a successful DC 14  Constitution  saving throw or be slowed until the start of its next turn. In addition, any creature that has been diseased by a nihileth or a nihilethic zombie takes 7 (2d6) cold damage every time it starts its turn within the aura. \n'b'  Infecting Telepathy . If a creature communicates telepathically with the nihileth, or uses a psychic  attack  against it, the nihileth can spread its disease to the creature. The creature must succeed on a DC 14  Wisdom  save or become infected with the same disease caused by the nihileth\xe2\x80\x99s tentacle  attack . This ability replaces an aboleth\xe2\x80\x99s Probing Telepathy ability. \n'b'\n'b' Actions \n'b'\n'b'  Multiattack . The nihileth makes three tentacle attacks or three withering touches, depending on what form it is in. \n'b'  Tentacle (Material Form Only) .  Melee Weapon Attack : +9 to hit, reach 10 ft., one target.  Hit : 12 (2d6 + 5) bludgeoning damage. If the target creature is hit, it must make a successful DC 14  Constitution  saving throw or become diseased. The disease has no effect for 1 minute; during that time, it can be removed by  lesser restoration  or comparable magic. After 1 minute, the diseased creature\xe2\x80\x99s skin becomes translucent and slimy. The creature cannot regain  hit points  unless it is entirely underwater, and the disease can only be removed by  heal  or comparable magic. Unless the creature is fully submerged or frequently doused with water, it takes 6 (1d12) acid damage every 10 minutes. If a creature dies while diseased, it rises in 1d6 rounds as a nihilethic zombie. This zombie is permanently dominated by the nihileth. \n'b'  Withering Touch (Ethereal Form Only) .  Melee Weapon Attack : +8 to hit, reach 10 ft., one creature.  Hit : 14 (3d6+4) necrotic damage. \n'b'  Form Swap . As a  bonus action , the nihileth can alter between its material and ethereal forms at will. \n'b'  Void Body . As a  reaction , the nihileth can reduce the damage it takes from a single source to 0. Divine damage can only be reduced by half. \n'b'  Tail (Material Form Only) . As per the aboleth action. \n'b'  Enslave (3/day) . As per the aboleth action. \n'b'\n'b' Legendary Actions \n'b' A nihileth may 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\xe2\x80\x99s turn. The nihileth regains spent legendary  actions  at the start of its turn. \n'b'\n'b'  Detect . As per the aboleth action. \n'b'  Tail Swipe . As per the aboleth action. \n'b'  Psychic Drain (Costs 2 Actions) . As per the aboleth action. \n'b'\n'b' Lair \n'b' While aboleths create their lairs underwater, spending most of their time submerged, a nihileth lair can be encountered out of the water, often in a cave or a ruined, abandoned city. \n'b' Lair Actions \n'b' On  initiative  count 20 (losing  initiative  ties), the nihileth can take a lair action to create one of the magical effects as per an aboleth, or the void absorbance action listed below. The nihileth cannot use the same effect two rounds in a row. \n'b'\n'b'  Void absorbance . A nihileth can pull the life force from those it has converted to nihilethic zombies to replenish its own life. This takes 18 (6d6)  hit points  from zombies within 30 feet of the nihileth, spread evenly between the zombies, and healing the nihileth. If a zombie reaches  0 hit points  from this action, it perishes with no Undead Fortitude saving throw. \n'b'\n'b' Regional Effects \n'b' The regional effects of a nihileth\xe2\x80\x99s lair are the same as that of an aboleth, except as following. \n'b'\n'b' Water sources within 1 mile of a nihileth\xe2\x80\x99s lair are not only supernaturally fouled but can spread the disease of the nihileth. A creature who drinks from such water must make a successful DC 14  Constitution  check or become infected. \n'b'\n'b' About \n'b' Eons ago, a group of aboleth left the Material Plane to wander through distant planes-seeing them through magical  scrying  was not enough, so these aboleth used astral magic and bodily travel to see far beyond normal realms. \n'b'  A Forgotten Tribe . As ages passed, memories of those who departed slowly faded from the minds of those aboleth who remained behind. Those few aboleth who did remember that long ago some of their kin had gone plane-wandering assumed that the wanderers must have died in distant hells or paradises. \n'b'  Changed by Planar Wandering . The plane-wanderers hadn\xe2\x80\x99t died. Instead, their eons-long exposure to alien realms and to the space between changed them, restructuring their life force and making them into something even more nightmarish-but better able to withstand both strange hells and golden realms of eldritch delight. \n'b'  Servants of the Void . They returned even more corrupt and powerful than they had left, and these wandering nihileths returned to the mortal world intent on spreading the influence of the Void and the utter evil they found in the vast darkness between worlds.'