Gangcheori 강철이

Huge dragon, chaotic evil

Armor Class 19 (natural armor)

Hit Points 253 (22d12 + 110)

Speed 40 ft., climb 30 ft., swim 40 ft.

STR 25 (+7) · DEX 14 (+2) · CON 21 (+5) · INT 12 (+1) · WIS 17 (+3) · CHA 19 (+4)

Saving Throws Dex +9, Con +12, Wis +10, Cha +11

Skills Perception +10, Stealth +8, Survival +10

Damage Resistances lightning; bludgeoning, piercing, and slashing from non-magical attacks

Damage Immunities poison

Condition Immunities blinded (see Black Cloud), poisoned

Senses blindsight 30 ft., darkvision 120 ft., passive Perception 20

Languages Draconic, understands Common but rarely speaks

Challenge 16 (15,000 XP)

Traits

Legendary Resistance (3/Day). If Gangcheori fails a saving throw, it can choose to succeed instead.

Black Cloud. A 15-foot-radius sphere of murky fog and hailstones surrounds Gangcheori and moves with it. The area is heavily obscured for all creatures except Gangcheori. A moderate wind (at least 10 mph) or three or more creatures spending their actions beating drums, gongs, or similar instruments disperses the cloud until the end of Gangcheori’s next turn.

Toxic Wake. Vegetation Gangcheori moves through becomes diseased for 24 hours. A creature that starts its turn touching or standing in this vegetation must succeed on a DC 18 Constitution saving throw or take 9 (2d8) poison damage and be poisoned until the start of its next turn.

Noise Aversion. If Gangcheori takes thunder damage or hears three or more creatures within 60 feet simultaneously using their actions to create loud, rhythmic noise (gongs, drums, shouts), it must succeed on a DC 18 Wisdom saving throw or become frightened for 1 minute. A frightened Gangcheori must spend its movement each turn moving at least 30 feet away from the noise source and can repeat the save at the end of each of its turns, ending the effect on a success.

Innate Spellcasting. Gangcheori’s innate spellcasting ability is Charisma (spell save DC 19). It can innately cast the following spells, requiring no material components:

3/day each: control water, gust of wind, water breathing

1/day each: earthquake, tsunami

Xanathar’s Guide to Everything

Actions

Multiattack. Gangcheori makes three attacks: one with its Bite and one with its Hooves.

Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 20 (2d12 + 7) piercing damage plus 14 (4d6) poison damage. The target must succeed on a DC 20 Constitution saving throw or be poisoned for 1 minute. While poisoned in this way, the creature is incapacitated by searing pain. The creature can repeat the save at the end of each of its turns, ending the effect on a success.

Hoof. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 16 (2d8 + 7) bludgeoning damage.

Hooves Stomp. Melee Weapon Attack: +12 to hit, reach 5 ft., one prone creature. Hit: 23 (3d10 + 7) bludgeoning damage. The target must succeed on a DC 19 Strength saving throw or be knocked prone.

Venom Flood (Recharge 5–6). Gangcheori exhales a torrent of poison in a 60-foot line that is 10 feet wide. Each creature in the line must make a DC 20 Constitution saving throw, taking 49 (14d6) poison damage on a failed save, or half as much damage on a successful one. A creature that fails the save is also knocked prone and poisoned for 1 minute (save ends at the end of each of its turns).

Brain-Gorge. When Gangcheori reduces a creature to 0 hit points with a Bite, it can suck out and devour the creature’s brain. Gangcheori regains 20 hit points and gains advantage on attack rolls until the end of its next turn.

Reactions

Hoof Smash. When a creature within 15 feet of Gangcheori hits it with an attack, Gangcheori makes a Claw attack against that creature.

Lair & Regional Effects

Gangcheori often lairs in flooded valleys or blighted forests. On initiative count 20 (losing initiative ties), it can take one lair action:

Gale. Strong winds fill a 60-foot radius. Ranged weapon attacks are made with disadvantage, and unprotected flames are extinguished. The effect lasts until initiative count 20 on the next round.

Hailstorm. Hail pelts a 20-foot-radius sphere Gangcheori can see. Each creature in the area must succeed on a DC 18 Dexterity saving throw or take 10 (3d6) bludgeoning damage.

Flash Flood. Water surges through a 30-foot-long, 10-foot-wide line. Creatures in the line must make a DC 18 Strength saving throw or be pushed 20 feet and knocked prone.

Lore

A four-legged, venomous dragon with rabbit-like ears. It can call down poisonous rain that kills vegetation;

One of the earliest references to Gangcheori appears in the 1614 encyclopedic work Jibong Yuseol (지봉유설) by the scholar Yi Sugwan. The text quotes an old saying: “Where Gangcheori passes, even autumn becomes like spring.” This means that after the creature moves through, nothing remains of the plentiful autumn harvest because it poisons every plant in its path. Furthermore, if you touch vegetation tainted by the monster’s venom, your skin immediately starts to fester.

In the 18th century Gangcheori’s image continued to develop, recorded by other scholars who noted rumors that during a flood in Yangsan County a Gangcheori appeared that could control the water level. This shows Gangcheori was not invented by a single author or region; it was a deeply rooted folk belief. The monster morphed according to local disasters and cultural traits, embodying not one specific element but the very idea of catastrophe itself.

From Korean Bestiary 5E, p. 36 · Fern Flower Press