I am currently running an Oriental Adventures (OA) campaign called The Divine Heir and the Jade Regent loosely based around the Pathfinder Adventure Path the Jade Regent with strong influences from Sekiro. The first adventure is called The Ashina Legacy and is essentially the The Brinewall Legacy set in and completely converted to an OA setting.
I had to rewrite the adventure intro and re-theme the monsters but it worked well. Here is the flowchart of the adventure (and campaign).
Taking something from Japanese Folklore I replaced the original adventure’s quickling with a triplet of kamaitachi. My PCs never encountered them though as they were very cautious about exploring the castle more than they needed to.
Medium fey (spirit), neutral evil
Armor Class 16
Hit Points 10 (3d4 + 3)
Speed 120 ft.
STR DEX CON INT WIS CHA
4 (-3) 23 (+6) 13 (+1) 10 (+0) 12 (+1) 7 (-2)
Skills Acrobatics +8, Perception +5, Sleight of Hand +8, Stealth +8
Senses darkvision 60 ft., passive Perception 15
Languages Common, Sylvan
Challenge 1 (200 XP)
Evasion. If the kamaitachi is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, it instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.
Keen Hearing and Smell. The kamaitachi has advantage on Wisdom (Perception) checks that rely on hearing or smell.
Spider Venom. The kamaitachi have envenomed their sickles with spider poison. The target must succeed on a DC 13 Constitution saving throw or be poisoned for 1 hour. If the saving throw fails by 5 or more, the target is also unconscious while poisoned in this way. The target wakes up if it takes damage or if another creature takes an action to shake it awake. Otherwise, a creature that fails the save begins to become paralyzed and is restrained. The restrained creature must repeat the saving throw at the end of its next turn, becoming paralyzed on a failure or ending the effect on success.
Multiattack (1/Day). The kamaitachi makes three sickle claw attacks.
Sickle Claws. Melee Weapon Attack: +8 to hit, reach 5 ft., one target.
Hit: 7 (1d2 + 6) piercing damage and 2 (1d4) necrotic damage. The creature takes 2 (1d4) necrotic damage at the start of their turn unless they make a DC 10 Wisdom (Medicine) skill check or are healed by magic.
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target.
Hit: 5 (1d4 + 6) piercing damage.
The kamaitachi always appears in threes.