If you decided to stick with Lord Kuro rather than siding with Owl then your journey will eventually take you to the Fountainhead Palace. Right at the start of your journey through this region you’ll once again encounter an enemy who you’ve already beaten once in the Ashina Depth. Namely, it’s the Corrupted Monk, but this time she’s in her true form, and she’s got three bloody phases! Don’t let that panic you though, her Posture bar breaks quickly and she isn’t an apparition, so we don’t need any Divine Confetti for this fight.
From the Fountainhead Palace Sculptor’s Idol, run through the gate and start running over the bridge and Corrupted Monk will dive over the gate in front of you. We’re going to give ourselves a head start in this fight by going straight on the offensive here, so let her land and then charge her and start attacking and you should get four hits in before she’s even started to fight.
After this, the first phase is all about following the same tips from the Corrupted Monk fight in the Ashina Depths; Deflect her attacks, jump kick her to avoid her sweeping Perilous attack, Mikiri Counter her Perilous thrust attack, and get your own hits in while Corrupted Monk is recovering from her own attacks – she’s slow, you’re not.
Keep at this and you’ll open her up for the first Deathblow pretty quickly. When you hit the first Deathblow, Corrupted Monk will disappear and the bridge will be engulfed in fog. When this happens, grapple up to the trees above as three phantom versions of the Monk are about to appear. You can try and fight these if you want but there’s absolutely no point, so grapple up to the trees and wait it out and after a few seconds the phantoms will disappear, then you can drop back down and take on the Corrupted Monk again following the same tips from the first phase. This fog and the phantoms might reoccur during the second phase, so if it does just grapple back up to the trees and wait it out again.
Once you hit the second Deathblow, Corrupted Monk will fall to the floor only to raise to her feet with a millipede protruding from her neck. Lovely.
This third phase is identical to the first (the phantom attack won’t happen) with one distinct difference, a new Perilous attack where she spews Terrori-inducing gunk at you. When you see her retching and getting ready to spit, Step Dodge around her or jump to the side and then get a few hits of your own in before she recovers.
Following all of the tips from the first phase and adapting to the new Perilous attack will soon open Corrupted Monk up for the final, deadly Deathblow.
Killing her will earn you Memory: True Monk, which can be used at a Sculptor’s Idol to permanently increase Attack Power, the Dragon’s Tally Board, and a bunch of xp.