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).
Straight up conversion from the adventure with a name change and some added effects.
NAMEKUJI (SLUGWORT) the OGRE JAILER
Large giant, chaotic evil
Armor Class 11 (hide armor)
Hit Points 85/130 (10d10 + 30)
Speed 40 ft.
STR DEX CON INT WIS CHA
19 (+4) 8 (-1) 16 (+3) 5 (-3) 7 (-2) 7 (-2)
Saving Throws CON +5, WIS +0
Damage Vulnerabilities fire
Senses darkvision 60 ft., passive Perception 8
Languages Common, Giant
Challenge 4 (1,100 XP)
Reckless. At the start of his turn, Slugwort can gain advantage on all melee weapon attack rolls during that turn, but attack rolls against him have advantage until the start of his next turn.
Multiattack. Slugwort makes two attacks with his great hammer.
Great Hammer. Melee Weapon Attack: +6 to hit, reach 5 ft., one target.
Hit: 13 (2d8 + 4) bludgeoning damage. “This weapons head is actually shaped like a giant fist”.
Javelin. Melee or Ranged Weapon Attack: +6 to hit, reach 5 ft. or range 30/120 ft., one target.
Hit: 11 (2d6 + 4) piercing damage.
Hammer Time (Recharge 6). Melee Weapon Attack: +6 to hit, reach 10 ft., one target.
Hit: 13 (2d8 + 4) bludgeoning damage, and the target must succeed on a DC 14 Constitution saving throw or be knocked unconscious for 1 minute. The unconscious target repeats the saving throw if it takes damage and at the end of each of its turns, ending the effect on itself on a success.
Atomic Throw. If an attacker misses Slugwort he may use his reaction to grab the attacker and throws it across the room by making a melee weapon attack (+6). The target lands 10 feet away, falls prone and takes 13 (2d8 + 4) bludgeoning damage.
Hammer Spasms. When Slugwort is first bloodied Hammer Time recharges and he can use it as a reaction.
Red Eyed Ogre. When Slugwort is first damaged he flies into a rage and gains all the traits marked in red.
Lucky rock is an earth elemental gem. However, this summons an elemental terror – toichi no kansen – instead of a standard elemental. The gem is reusable but once the toichi no kansen has consumed 7 HD of creatures it becomes jimen no oni and turns on the party.