Pure Vessel

"Chosen vessel, raised and trained to prime form. "Deepest silence in holy shell, Given nail and named a Knight, Bound by chain and egg and spell, Hear Our plea! Reveal thy Light!""

- Prayer to the Vessel

The Pure Vessel is a quest boss in Hollow Knight introduced in Godmaster. They are the prime version of the Hollow Knight, unaffected by the Infection.

Behaviour and Tactics
Pure Vessel uses the following attacks:


 * Soul Daggers: Pure Vessel moves to either side of the arena, faces the Knight, and raises their hand. The hand glows white while they summon seven daggers that shoot towards the Knight in straight lines along an arc. The daggers are summoned sequentially, the first one firing at an angle towards the floor, and the last one firing straight up.
 * Triple Slash: Pure Vessel slashes with their Nail three times. Each slash of their Nail moves Pure Vessel forward, covering about 1/3 of the arena in total. The slashes cover enough space that they can damage the Knight even if they are not directly in front of Pure Vessel.
 * Soul Pillars: Pure Vessel either leaps or teleports into the air above where the Knight was and then slams into the ground, causing pillars of Soul to jut up from the floor of the arena. These pillars are equally spaced, allowing just a bit of safety between them, and they span the entire arena. The root of these pillars has larger hitbox than the tip.
 * Lunge: Pure Vessel draws their Nail up and lunges along the ground towards the Knight. This lunge covers about 50% of the arena.
 * Parry: Pure Vessel takes up a defensive stance with their Nail. If the Knight damages them after their Nail shines, they will take no damage from the hit and instead will respond by shifting forward a little and slashing with their Nail.
 * Focus: Pure Vessel begins focusing Soul kind of like the Knight does. However, unlike the Knight, Pure Vessel surrounds themselves with a circular aura that eventually explodes. The first aura becomes dangerous shortly after the rocks float. Shortly after, six smaller auras appear randomly throughout the arena. Then these smaller auras explode in rapid succession in the order in which they appeared. Pure Vessel will begin another attack as the final small explosion occurs. They start using this attack when they reach 1056 health.
 * Void Tendrils: Pure Vessel opens their cloak, revealing several flailing void tendrils, including two larger ones. About three quarters of a second later, the two larger tendrils lash out across about 60% of the arena. The lashing continues for about three quarters of a second. They start using this attack when they reach 528 health.
 * Jump: When the Knight has remained off the ground for too long, Pure Vessel will launch themselves at the Knight's location, dealing contact damage.
 * Teleport: Pure Vessel will teleport within the arena to prepare for an attack or dodge the Knight.
 * Backstep: Pure Vessel will quickly backstep away from the Knight if they get too close and then perform another attack.

Pure Vessel's fight is a quick-paced fight. Pure Vessel will chain attacks together without moving between them, will back step between attacks, or teleport between attacks. It is recommended that players practice enough to recognize Pure Vessel's attacks quickly and be equally quick with their reactions. Because there is little to no chances for healing, extensive uses of invincible frame (Shade Cloak and Descending Dark) is one of the key point to keep up with the fight.
 * To handle Triple Slash: jumping over it, shadow dashing through it, or Descending Dark. Jumping over the Triple Slash requires either a well-timed pogo or double jump (thanks to Monarch Wings) to avoid the second slash. Once players are past Pure Vessel, there can be an opportunity to damage them again before they attack again. Pure Vessel has noticeable delay before attack, and panic shadow dashing toward him may easily cause a contact hit.
 * The Knight can dodge lunge attack using the same way as it dodge Triple Slash, and can even pogo of a hit or two. If player jump over Pure Vessel, do not dash back to chase it, as it may instantly turn around and launch a Triple Slash. If Pure Vessel is off screen and player hear the sound cue, it is better to dash away then come back to land some hits after it stop the attack. Unlike Triple Slash, Pure Vessel's lunging speed is very fast, so it is not recommended trying to dodge the attack with Descending Dark.


 * Once Pure Vessel is above the Knight for Soul Pillars, getting out of the way is most important. Then players need to put themselves in between the Pillars, which can even mean pogoing on Pure Vessel. There's time to damage Pure Vessel while waiting for the Pillars to go away. Player can always play safe and use Descending Dark to dodge the attack entirely.


 * The safest option when Pure Vessel gets into the Parry stance is to not attack, then player will have a chance to land some hits before Pure Vessel return to it's routine. Or they can intentionally trigger the riposte and handle that with usually a shadow dash.


 * A nifty thing about the Soul Daggers attack is the telegraphed lines of travel showing players the safe gaps between the Soul Daggers. Players can stay far away and cast Shade Soul or they can get in close and deal damage. Shadow dashing on the ground is almost guarantee a safe dodge, and can even close the distance for some hits. Be careful when dashing toward Pure Vessel mid-air, as the Knight can easily be caught by the remaining daggers.


 * When Pure Vessel begins focusing, players can stay far away and use Shade Soul, then dashing in get in some quick Nail damage before the explosion, or time Descending Dark to avoid the explosion. After the initial explosion, it's all about doing damage while remaining safe from the follow-up explosions.


 * For Void Tendrils, it's most important to get out of the way, whether that's getting out of range, getting above, or getting behind Pure Vessel. When out of range, casting Shade Soul is a good option. When above, pogoing on Pure Vessel and/or casting Descending Dark is viable. Once behind, players can do whatever they want while the attack occurs.

The safest time to heal is when Pure Vessel is staggered. Without charms, players can heal 1 mask safely or maybe 2 if they start healing as soon as Pure Vessel is staggered. Players can heal 1 mask during Soul Pillars if players start healing before the Pillars form and Pure Vessel takes a moment before attacking again; when Pure Vessel Focuses (or 2 masks if a smaller explosion doesn't spawn on the player); during Soul Daggers if the player is already in a safe position; during a parry if the player predicts it; and when players are out of range of Void Tendrils.

Quick Focus helps but generally won't provide enough time to get another mask during these no-charm moments but does grant more time to safely react to Pure Vessel. Players can eke out a third mask when Pure Vessel is staggered. Adding Shape of Unn to Quick Focus grants players enough maneuverability to safely heal 1+ masks during all of these moments.

NOTE: The Dream Nail and Flukenest do not work or have an effect against Pure Vessel.

Trivia

 * The Pure Vessel was shown through the trailer of Godmaster to be fully armoured, however, this armour is only displayed for a couple of seconds at the beginning of the Pure Vessel fight before being ripped off.
 * Pure Vessel, along with the Hollow Knight, is the only boss whose title appears at the top of the screen.
 * Unlike the Hollow Knight, Pure Vessel's pre-battle cry is silent.
 * In the release, Pure Vessel cannot be Dream Nailed, but has the following cut Dream Nail dialogue:
 * Do not think...
 * Do not speak...
 * Do not hope...
 * Do not...

References

Чистый Сосуд Reines Gefäß Ricettacolo Puro Nieskalany Vessel