I have no idea what her deal is but she hits like a truck. Hope someone figures out a good way to deal with her.

It appears divine confetti is the best way to deal with her.

Don't bother fighting her without divine confetti

Hardest mini-boss so far. She's pretty cheap, honestly. Using the Mortal Strike is unblockable by her (still deals damage) but it's extremely risky as if you whiff you'll eat most of your health in damage. Flowing Waters is also good for easy posture damage, but again, whiff it and you die.

Recommend getting prayer beads and killing bosses for attack power if you don't have divine confetti or want to save it for the headless fellows. Upgraded Flame Prosthetic can set her on fire if you want to safely lower her HP so her posture bar regens slowly or stops regenerating entirely and you can always get a head-start by setting her on fire before you start the fight. When you swing at her twice she'll usually "deflect" your hit and try to counterattack, my experiences is that back-jumping avoids it everytime safely. Stay out of her range and watch out for her raising her hand because she'll spam her wombo combo that will melt your posture. If you have posture and she can't regen posture then take her wombo combo head-on and she'll commit to lethal sweep you can jump over. She also has a jumping motion attack where she glides in a side-arc motion, just deflect it and swing at her to interrupt the lethal attack if you want the health chip dmg. I forgot if the lethal was a sweep but you could opt in for a jump bounce. When it hits the 2nd phase, blast her with fire at the start where she's recovering from the your finisher blow. She'll be more aggressive in the sense that she'll zoom close to you across a large distance and go for an attack. She will also no longer always lethal sweep after the wombo combo so its not worth taking the risk. Slow and Steady my guys.

Wondering if leaving her alone and trying to find this "guy" coming back to her will do something. I feel like she has more to her.

For those struggling: you can cheese her with some good positioning. To her left is a small rock wall. Position yourself between the wall and the rocks and bait her to you. Then go to the other side of the rock wall and stand a moderate distance away so that her attacks don't reach you. Take the mortal draw combat art (gained upon recieving the mortal blade) and spam that sucker. Make sure to reposition between attacks so that the rock wall is always between you and her. Should she get out of there just bait her back in there again and repeat.

there's no need to use anything other than your sword here. parry more than you attack. you will only be able to get 1 or 2 attack in most of the time, and the purpose of that will be to sustain her posture gauge.

Killed her at 3rd try. Just parry every attack and when she's going to make the thrust attack (with the red symbol) jump on her, it'll break her posture quickly.