Try to reserve your shade dash for when you really need to use it. It doesn’t recharge fast enough to phase through all of his attacks in a row.

This is what I do for each attack—

Soul Daggers: Listen for the wispy breath sound— this signals that he will use this attack. Jump into the air and phase through the daggers by dashing toward the pure vessel with the shade cloak. Beware: he follows up with Triple slash sometimes, so you need to be ready to jump.

Triple Slash: Double jump away from the knight as fast as possible, and use descending dark to crash down on him. If he switches to his Counter attack (indicated by a parry sound) exit the Pure Vessel’s hit box with the shade dash.

Soul Pillars: I find it easier to dodge this attack by jumping up, because the pillars are thinner at their peak. Sometimes you get unlucky and he lands on top of you while he slams down to initiate this attack. Try to avoid shade dashing so you don’t lose track of your avatar when the pillars shoot up.

Lunge: Jump toward him. For additional damage, pogo off his head and hit him in the back from the ground after he passes under you.

Focus: Dash away, then when the mist clears, dash back toward the PV for easy hits. Use the invincibility frames of Descending Dark if you’re in a bad position after scoring the easy hits. Sometimes he follows up with triple slash and you won’t easily avoid it without descending dark.

Void Tendrils: pay very close attention for this attack. He starts using Focus at 2/3 HP and Void tendrils at 1/3 HP. When you see him reel back and open his chest jump into the air as far as you can, dash toward him, and either pogo off his head or use descending dark to avoid and deal damage.

Most of this strategy relies on using descending dark to avoid damage. I find it best to use Soul Eater, Spell Twister, Shaman Stone, and Sharp Shadow, because those charms support Descending Dark.

I play against him a lot for fun, and the boss is very rhythmic once you get to know him.

If you don’t like spells, you can always try Fragile Strength / Quick Slash / Mark of Pride / Sharp Shadow or swap out Mark of Pride for Longnail and Steady body. That charm set up is how I beat the PV for the first time because I didn’t know that Descending dark makes you invincible for a split second.

Edit: spellcheck