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).
Here is a set encounter. For those familiar with the original Brinewall Legacy it replaced the doppelgänger creature posing as a halfling (a Korobokuro in my game). My players, being level 1, avoided exposing the swamp too much and stayed focused on their goal – executing the bake mono – so they never had this encounter.
VOLOROG THE KUMO
Medium aberration (shapechanger, yokai), neutral evil
Armor Class 15 (leather armour)
Hit Points 52 (8d8 + 16)
Speed 50 ft.,climb 30 ft.
STR DEX CON INT WIS CHA
11 (+0) 18 (+4) 14 (+2) 11 (+0) 12 (+1) 14 (+2)
Skills Deception+6, Insight+3
Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks that aren’t crystal
Condition Immunities charmed
Senses darkvision60 ft., passive Perception 11
Languages Common, Oni
Challenge 3 (700 XP)
Ambusher. The kumo has advantage on attack rolls against any creature it has surprised.
Shapechanger. The kumo can use its action to polymorph into a Small or Medium humanoid it has seen, or back into its true form. Its statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn’t transformed. It reverts to its true form if it dies.
Surprise Attack. If the kumo surprises a creature and hits it with an attack during the first round of combat, the target takes an extra 10 (3d6) damage from the attack.
Spider Climb. The kumo can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Tongues. The kumo is under a constant tongueseffect (as the spell).
Web Walker. The kumo ignores movement restrictions caused by webbing.
Multiattack. The kumo makes two attacks.
Paralysing Bite. Melee Weapon Attack:+6 to hit, reach 5 ft., one creature.
Hit: 6 (1d6 + 3) piercing damage plus 3 (1d6) poison damage. If the target takes any poison damage and is a creature, it must succeed on a DC 10 Constitution saving throw or be paralyzedfor 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Spit Poison. Range Weapon Attack:+6 to hit, range 15 ft., one target.
Hit: 7 (1d6 + 4) poison damage. If the target takes any poison damage and is a creature, it must succeed on a DC 10 Constitution saving throw or be paralyzedfor 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Spit Web. Range Weapon Attack:+6 to hit, range 30 ft., one target.
Hit: The target is restrainedby webbing. As an action, the restrainedtarget can make a DC 12 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 10; hp 5; vulnerability to fire damage; immunity to bludgeoning, poison, and psychic damage).
Treasure: +1 Spirit Emblem.