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).
Converted from 3e.
Minor Toshigoku Spirit
Medium undead (yokai), neutral evil
Armor Class 14 (tattered lamellar)
Hit Points 45 (6d8 + 18)
Speed 30 ft.
STR DEX CON INT WIS CHA
15 (+2) 14 (+2) 16 (+3) 10 (+0) 13 (+1) 15 (+2)
Skills Perception +3, Stealth +4
Damage Resistances necrotic; bludgeoning, piercing, and slashing from nonmagical attacks that aren’t crystal
Damage Immunities poison
Condition Immunities exhaustion, poisoned
Senses darkvision 60 ft., passive Perception 13
Challenge 3 (700 XP)
Soul Rot. The fallen samurai carries an infectious disease called Soul Rot. If a living creature infected, it becomes poisoned for the duration of the disease. If the disease hasn’t been cured within 48 hours, the carrier dies an agonizing death and rises again as a taint zombie within 1d4 hours unless the remains are burned or cleansed of the disease. All creatures native to the Shadowlands are immune to Soul Rot. A creature is exposed to infection every time it takes necrotic damage from the fallen samurai. The target must make a DC 13 Constitution saving throw against disease. On a failure, the creature is infected by Soul Rot.
Tainted Undeath. If the fallen samurai is reduced to 0 hit points, roll a d10 at the end of each of its turns. On a 10, the fallen samurai returns to life with a 14 hit. This trait does not work if the fallen samurai’s remains are burned, or if the fallen samurai dies from fire or radiant damage.
Sunlight Sensitivity. While in sunlight, the fallen samurai has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Multiattack. The fallen samurai makes two longsword attacks or two longbow attacks. It can use its Life Drain in place of one longsword attack.
Soul Rotting Katana. Melee Weapon Attack: +4 to hit, reach 5 ft., one target.
Hit: 6 (1d8 + 2) slashing damage, or 7 (1d10 + 2) slashing damage if used with two hands plus 5 (1d6 + 2) necrotic damage. The target must succeed on a DC 13 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.
A humanoid slain by this attack rises 24 hours later as a taint zombie under the wight’s control, unless the humanoid is restored to life or its body is destroyed. The wight can have no more than twelve zombies under its control at one time.
Daikyu. Ranged Weapon Attack: +4 to hit, range 150/600 ft., one target.
Hit: 6 (1d8 + 2) piercing damage.
Dressed as a crane warrior, one of the former defenders of Ashina.