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In this set of blog entries I aim to convert the original 1e Oriental Adventure monsters to 5e to provide some extra fodder for an OA campaign.  I am using both the original 1e source and the updated 3e source as reference for the build.  Kappa to me are basically ancient versions of TMNT so I always picture them less ugly/horrific than the typical traditional Japanese depiction.


Small humanoid (yokai), any chaotic alignment (usually neutral)

Armor Class 15
Hit Points 65 (10d6 + 30)
Speed 20 ft., swim 40 ft.

18 (+4) 17 (+3) 17 (+3) 7 (-1) 14 (+2) 11 (+0)

Senses passive Perception 12
Languages any one language (usually Common)
Challenge 2 (450 XP)

Amphibious. The kappa can breathe air and water.

Head Bowl. The indentation on the top of a kappa’s head is filled with water from the lake or stream where the kappa lives. Movement and ordinary actions (even combat) does not cause the water to spill; however, a character grappling a kappa can empty the bowl by winning an opposed grapple check. The kappa also has disadvantage on Strength checks (including the attack action), and negates its regeneration ability

Improved Grab. The kappa has advantage on grapple checks.

Regeneration. The kappa regains 5 hit points at the start of its turn. If the kappa’s head bowl is emptied of water it losses this trait.

Unarmored Defense. While the kappa is wearing no armor and wielding no shield, its AC includes its Wisdom modifier.

Water Immunity. Kappas are immune to water-based spells, including any spell with the word “water” in its name and shugenja or wu jen spells from the water element.

Multiattack. The kappa makes two melee attacks with its claws.

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target.
Hit: 7 (1d6 + 4) bludgeoning damage and the target is grappled (Escape DC 13).

Kappas are a race of malevolent, diminutive humanoids that bear a strong resemblance to turtles. Despite their smallsize (an average kappa stands just over 2 feet tall and weighs about 20 pounds), kappas are accomplished martial artists, focusing on techniques of grabs and throws.  Kappas have a stooped posture and a hard shell covering their backs, while thick but supple scales protect the rest of their bodies.  Their scales are usually green with yellow splotches, but occasionally dull blue with yellowish brown accents.   They have protruding pot bellies with pouches near the base of the abdomen. Their feet are heavy and wide, with three webbed toes ending in hooked claws. Their hands are similarly webbed and clawed, though they are quite dexterous.  Their heads are flat and plump, with a bowllike indentation on the top of the head, which holds water from the kappa’s home lake, river, or pond. Their broad mouths are filled with multiple rows of hooked teeth. Their round, bright eyes are usually red or yellow, and covered by a transparent lid that enables them to see clearly underwater.  Most kappas have long noses resembling a bird’s beak, but some have shorter, more humanlike noses. Kappas speak Common and their own language.

Generally, a kappa’s behavior is unpredictable and extreme. Kappas delight in the discomfort of others, but they are usually polite at first, even to potential prey.  Potential victims can sometimes placate them by appealing to their vanity — complimenting their manners or offering gifts, for example.  But a hungry, insulted, or simply ornery kappa shows no mercy. Kappas enjoy rending victims with their claws, but sometimes engage in wrestling contests.

Kappa are so proud of their prowess as hand-to-hand fighters that they often offer a victim the chance to wrestle. If the victim wins, the kappa will grant him free passage. If he loses, the kappa will drag him underwater and eat him.

One of the kappa’s favorite contests is finger wrestling. The kappa and the victim link their smallest fingers while standing on the shore, then attempt to pull each other into the water.  To simulate this contest, the kappa and the victim each attempt opposed Strength checks.  If both wrestlers succeed or fail in a particular round, nothing happens. If the victim succeeds and the kappa fails, the victim wins and is allowed to go on his way. If the kappa succeeds and the victim fails, the victim has been pulled underwater.

Kappa live in bodies of fresh water, making their lairs under rocks and bridges. They have an extreme aversion to salt water, and exposure to salt water for extended periods of time usually is fatal.

A kappa lair is often marked by a large stump or flat rock near the surface of the water. Usually, the landmark is concealed by a circle of high weeds or marsh grass. The kappa uses this stump or rock as a sunning spot. Under the water, a large rock or pile of stones conceals the entrance to the actual lair, which opens into a tunnel that leads to a small, water-filled cavern. A hole in the cavern floor contains the kappa’s treasure, which comprises coins, jewelry, and magical items taken from victims. The treasure hole is concealed by a large stone.

A kappa family consists of 2-6 adult males with an equal number of females. The number of children equals the total number of adults. Mating is initiated by the females, who vigorously pursue the male of their choice until the male submits. A female lays 1-6 eggs every year, about half of which actually hatch. The mother keeps the eggs hidden in her pouch, and carries the young in her pouch for up to a year after they hatch. A young kappa grows quickly, reaching full maturity in about five years. They can walk, swim, and speak as soon as they hatch, however. Kappa live to be about 100 years old.

These creatures are oblivious to the problems and concerns of others – even members of their own families. A kappa rarely will come to the aid of endangered kin unless he himself would benefit. Before he will act, his own safety must be reasonably assured and he must be fairly confident that his efforts will lead to personal gain – such as treasure or food.
Humans who share an area with a kappa learn to throw food and trinkets into his water as an offering. These humans write the names of their family members on the gifts, so the kappa is aware of their source. On rare occasions, a kappa acquires a deep respect for a particular human who is especially helpful, deferential, or threatening; in such cases, the kappa may offer to teach the human some of its skills.

Kappa eat humans, cows, and sheep when they can get them; otherwise they content themselves with fish. They are especially fond of horseflesh, and often attempt to drag these animals to their doom. Kappa also enjoy cucumbers and melons.


Smarter-than-Some. Unusually intelligent specimens kappa (about 10% of adult males) can cast spells. This talent is innate; the spellcaster does not have to memorize the spells. However, the kappa only can cast spells while he is within one mile of his home. The creature casts spells as if he were a wu jen whose level equals the kappa’s Hit Dice. Kappa have access to any of the wu jen spells, but they favor the water-based magic.

Last-Laugh.  Particular ancient kappa – those who manage to survive more than a 100 years generally – release a death curse when they die. The death curse is cast by the kappa’s spirit on the opponents who defeated him in his final battle.  Up to four opponents can receive the death curse. Each affected opponent must make a DC 15 Charisma saving throw exactly four rounds after the kappa’s death. Those who fail their saving throws acquire a permanent -4 penalty to their attack and saving throw rolls; additionally, everyone within a 30’ radius of a cursed character suffers disadvantage to their attack and saving throw rolls for as long as they remain within that radius. The death curse only can be lifted by a remove curse spell.

Vampiric. Vampiric kappa’s are very rare and are always chaotic evil.  They gain the following additional trait and attack option:

Unbreakable Hold. A creature grappled by a vampiric kappa can not break the hold until the kappa is dead, its bowl of water is emptied or it willingly lets go.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., a creature that is grappled by the kappa, incapacitated, or restrained. Hit: 7 (1d6 + 4) piercing damage plus 3 (1d6) necrotic damage. The target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and the kappa regains hit points equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.


Posted in 5e, Dungeons & Dragons, Monstrous Compendium, Oriental Adventures

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