SESSHOSEKI
Lore
Sesshoseki, or the “Killing Stone,” is a cursed object that serves as a spiritual prison for an extraordinarily powerful and malicious being. Its name comes from its ability to kill any living creature that draws near or touches the boulder’s surface. The danger is two-fold: first, the physical stone, saturated with negative energy; second, the spirit sealed inside it, believed to be the legendary nine-tailed fox Tamamo-no-Mae. Folklore says that after this fox died, her body turned to stone, and her vengeful spirit, Hoji, fused with the rock forever, turning it into a source of ceaseless malevolent energy known as jãki.
The stone sits in the volcanic region of Nasu, Tochigi Prefecture, at the foot of Mount Chausu, near the Nasu-Yumoto hot springs. The local geology amplifies the threat: cracks in the rock constantly vent hydrogen sulfide and sulfur dioxide, accounting for the deadly fumes around the boulder. Legend treats these gases as the tangible form of the poison the demon continues to spew even after death. A barren field stretches around Sesshoseki, traditionally viewed as the boundary of the realm of the dead. For centuries the stone has been kept under ritual guard: a sacred rope is strung around it, meant both to contain the evil power and to warn travelers of the mortal danger.
Stat block
Armor Class
17 (natural armor, hardened lava)
Hit Points
75 (10d10 + 20)
Speed
0 ft. (immobile)
Saving Throws
Con +5, Wis +5
Skills
—
Damage Vulnerabilities
thunder (shatters the crust)
Damage Resistances
cold, fire, lightning; bludgeoning, piercing, and slashing from non-magical attacks
Damage Immunities
poison, psychic
Condition Immunities
blinded, charmed, deafened, exhaustion, frightened, paralyzed, petrified, poisoned, prone, restrained
Senses
blindsight 60 ft. (creatures in the miasma only), passive Perception 12
Languages
telepathy 60 ft. (understands Common and Infernal)
Challenge
3 (700 XP)