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 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).
The original has a giant manbat creature, thought this was more appropriately thematically.
KOMORI YOKAI (BAT)
Medium fiend (yokai), neutral evil
Armor Class 16 (natural armor)
Hit Points 49 (9d8 + 9)
Speed 30 ft., fly 60 ft.
STR DEX CON INT WIS CHA
9 (-1) 20 (+5) 12 (+1) 6 (-3) 15 (+2) 16 (+3)
Skills Perception +4, Stealth +7
Damage Resistance bludgeoning, piercing and slashing from nonmagical attacks that aren’t crystal.
Damage Vulnerabilities radiant
Condition Immunities frightened
Senses darkvision 120 ft., passive Perception 14
Languages Common (cannot speak)–
Challenge 3 (700 XP)
Fear Frenzy. The komori yokai has advantage on attack rolls against frightened creatures.
Sunlight Sensitivity. While in sunlight, the komori yokai has disadvantage on attack rolls and on Wisdom (Perception) checks that rely on sight.
Blood Thinning Venom. When a creature suffers necrotic damage from the komori yokai, the creature must make a DC 12 Constitution saving throw. On a failed save, the creature becomes poisoned and takes 2 (1d4) necrotic damage at the end of each of its turns for 3 turns. Each time a creature fails the saving throw while already affected, the damage increases by 2 (1d4) necrotic damage and the duration is reset.
Actions
Screeching Attack. The komori yokai uses screech if available and then a claw attack.
Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target.
Hit: 8 (1d6 + 5) slashing damage plus 14 (4d6) necrotic damage plus blood thinning venom.
Frightening Screech (Recharge 5–6). The komori yokai screeches. Each creature within 30 feet of it that can hear it must succeed on a DC 13 Wisdom saving throw or be frightened of it for 1 minute. The frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the komori yokai’s Frightening Screech for the next 24 hours.