This floating creature has numerous writhing tentacles protruding from a body that is hidden inside an enormous shell. The colors of its body shift slowly between grays, greens, and even deep purples.

Otherborn. Kachlians form in the space between spaces, birthed where madness prevails. They find their way to the darkened caverns beneath the ground through portals of chaos and darkness—breaches in the fabric of reality caused by concentrations of turmoil, despair, and insanity. They are no strangers to the plateaus of Leng, and its denizens give wandering kachlians a wide berth.

Eater of Souls. The kachlian consumes the souls of creatures, preferring intelligent and enlightened prey. When it consumes a creature, the creature’s soul is torn to pieces. The kachlian absorbs the parts it considers valuable into its own being and discards the rest. These partial souls often combine into a twisted amalgam of spirits called a chimeric phantom. Despite the pain of their tormented creation and existence, chimeric phantoms often remain near the kachlian who created them, providing protection and limited companionship.

At Home Everywhere. Kachlians carry great shells on their backs, remains of unknown creatures from the kachlians’ home plane. The interior of each shell has a pocket of extra-dimensional space that holds the kachlian’s belongings. The older and more powerful the kachlian, the larger this extra-dimensional space. It is said some ancient kachlians have shells which contain several rooms filled with centuries of wealth. When a kachlian is slain, any creature can access the extra-dimensional space inside the shell; however, the space gradually fades over one month. An object in the extra-dimensional space when it fades is destroyed. A creature in the extra-dimensional space when it fades is deposited in a random location on the Astral Plane.

Kachlian

Huge aberration, neutral evil
Armor Class 16 (natural armor)
Hit Points 157 (15d12 + 60)
Speed 0 ft., fly 40 ft. (hover)

STR	DEX	CON	INT	WIS	CHA
18 (+4)	10 (+0)	19 (+4)	16 (+3)	15 (+2)	9 (-1)

Damage Resistances bludgeoning
Condition Immunities stunned, paralyzed, prone
Senses darkvision 120 ft., passive Perception 12
Languages Deep Speech, Undercommon
Challenge 8 (3,900 XP)

Consume Soul. A creature slain by the kachlian can’t be restored to life unless the kachlian is killed within 24 hours of slaying the creature. After 24 hours, the soul becomes part of the kachlian, and the creature can be restored only with a wish spell.

Spellcasting. The kachlian is a 7th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 14, +6 to hit with spell attacks). The kachlian has the following wizard spells prepared:
Cantrips (at will): chill touch, minor illusion, ray of frost, shocking grasp
1st level (4 slots): detect magic, hideous laughter, identify, magic missile
2nd level (3 slots): blindness/deafness, darkness, see invisibility
3rd level (3 slots): counterspell, slow
4th level (1 slots): confusion

Actions

Multiattack. The kachlian makes three attacks with its tentacles.

Tentacle. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 17 (3d8 + 4) bludgeoning damage. If the target is a Large or smaller creature, it is grappled (escape DC 16). The kachlian has three tentacles, each of which can grapple only one target.