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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.


“Koi of Unusual Size”

Huge beast, unaligned

Armor Class 13 (natural armor)
Hit Points 126 (11d12 + 55)
Speed 0 ft., swim 50 ft.

23 (+6) 11 (+0) 21 (+5) 1 (-5) 10 (+0) 5 (-3)

Skills Perception +3
Senses blindsight 60 ft., passive Perception 13
Languages —
Challenge 5 (1,800 XP)

Leap. The carp may leap out of the water either straight up or as a long jump of up to 20 feet.

Water Breathing. The carp can breathe only underwater.


BiteMelee Weapon Attack: +9 to hit, reach 5 ft., one target.
Hit: 22 (3d10 + 6) piercing damage.

Swallow. The carp makes one bite attack against a Large or smaller target. If the attack hits, the target is swallowed. The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside the carp, and it takes 10 (3d6) acid damage at the start of each of the carp’s turns.  The carp can have only one target swallowed at a time.  If the carp dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 5 feet of movement, exiting prone.


The giant carp is an overgrown cousin of the common carp, a food-fish favored by many people.  The giant carp lives in all types of fresh water lakes and rivers, if they are of substantial depth.  Its range extends from colder temperate waters to tropical climes.  It feeds as a scavenger, primarily digging through the ooze on the bottom.  However, they have been known to surface to attack small boats or swimmers.  Some have even taken the bait of a simple fishhook.

A single giant carp can supply the needs of a village for quite some time. Consequently, fishermen sometimes organize expeditions to bring back one of these beasts.  Such endeavors are highly dangerous and often result in the loss of life, however.

Some carps are actually intelligent and can speak.  These are usually kami of some type. pinrsani129 Their intelligence in 10 and they have the kami subtype.  They also have the lucky trait:

Lucky. When magikarp rolls a 1 on the d20 for an attack roll, ability check, or saving throw, it can reroll the die and must use the new roll.  It may also bless creatures it deems worthy with this ability for 1 day.

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

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