Watcher Knight

"Discarded shell of a Watcher Knight, re-animated by a swarm of infected flies. When these silent warriors fall in battle, their bodies split open and strange bugs come flying out. I wonder, what will come flying out of me when I die? Will my hopes and fears drift away into the darkness?"

The Watcher Knights are a single main boss in Hollow Knight. They guard Lurien the Watcher, one of the three Dreamers. Their Journal entry is unlocked at the end of the fight, regardless of how many there were.

Lore
The Watcher Knights used to defend the entrance to the Watcher's Spire and Lurien's dormant body. They eventually died while standing guard, leaving their shells behind.

In-game events
When the Knight tries to reach the end of the Watcher Knights' room, the gates close by themselves. The swarm of infected flies hovering above them then start entering the husks one after another. In doing so, they reanimate the Watcher Knights to defend Lurien's seal. Upon defeating each Knight, the flies within it escape the room and its husk splits apart. The fight is over once all six Knights in the first row have been defeated. Additionally, the husk second from the left can be broken before the start of the fight by bringing a chandelier down on it. Its support can be severed from a hidden space behind a breakable wall. This reduces the number of Watcher Knights to be fought to five.

Behaviour and Tactics
The Watcher Knights have three attacks and two manoeuvres:
 * Double Slash: Watcher Knight swings its giant nail twice. Watcher Knight swings horizontally first and follows it up with an overhead slash. It moves forward slightly with each swing.
 * Roll: Watcher Knight curls up into a ball and rolls along the floor of the arena until it hits the opposite wall. It is immune to Nail attacks while rolling, but can still be damaged using Spells.
 * Bouncing Roll: Watcher Knight curls up into a ball and bounces twice. When it does this attack, it attempts to target the Knight, which means it may simply bounce in place rather than travel around the arena. The first bounce takes Watcher Knight to the top of the arena and the second bounce takes it only to the middle. Similar to the Roll attack, it is immune to Nail attacks while bouncing, but can be damaged using Spells.
 * Back Roll: Watcher Knight curls up into a ball and rolls backwards to evade the Knight. This manoeuvre only occurs while two Watchers Knights are active.
 * Run: Watcher Knight, in an attempt to get closer to the Knight, sometimes runs towards them before performing another attack.

There are 6 Watcher Knights total, and the fight starts with only one Knight being reanimated. Once the Knight has been active for 20 seconds (just when the music gets louder) without being defeated, a second Knight is reanimated, joining the first. However, if the first Knight is killed quickly, two of the next Knights are reanimated together. Note that no more than two Knights can be active at once.

Since the Watcher Knights attack in groups, it is best to not get cornered by them. To prevent this, jump above them and hit them from the air, as their spinning jump is their only counter to aerial attacks.

Since they have fast attacks, the Quick Focus Charm is highly recommended for this fight. Another tactic is using Lifeblood Heart for a health boost, and Stalwart Shell to increase invincibility time, then damage the Knights while tanking their attacks. Using Sharp Shadow while having the Shade Cloak can make this fight easier as the Knight can dash through them dealing 1x Nail damage even when they are rolling; equipping Dashmaster as well increases the damage. Dream Wielder is also useful, as it allows the Knight to collect lots of SOUL from the Watcher Knights as they roar, because, while they are immune to damage during this state, they are not immune to being struck by the Dream Nail.

Another way to easily take them down is with Shaman Stone and Descending Dark. Three uses of Descending Dark with the damage boost is enough to kill a single Watcher Knight, and the invincibility frames keep the Knight safe long enough to jump and down-strike with the Nail before using another Descending Dark. When attempting this method, Spell Twister and Dream Wielder are very helpful to have equipped as well, in order to maintain high amounts of SOUL and lessen the number of times the Knight needs to hit the Watcher Knights with the Nail.

Directly to the left of the arena is a breakable ceiling (accessible via Mantis Claw), which reveals a secret area containing the anchoring of a chandelier. Striking it with the Nail drops the chandelier, crushing one of the corpses below and permanently reducing the number of reanimated Knights from 6 to 5.

Location
The Watcher Knights are located near the top of Watcher's Spire.

Trivia

 * Three Watcher Knights can be seen in a piece of promotional material.
 * The Watcher Knights were the sixth boss to be revealed through the Kickstarter under the name of Black Knight.
 * In an early development map, only one "Black Knight" (Watcher Knight) could be seen labelled.
 * The Watcher Knights were originally intended to be in the attic of another tower, which ended up being cut before release.
 * The inanimate bodies can be struck with the Dream Nail for SOUL before the battle starts, as well as struck with the Nail. This object behaviour is similar to the empty armour of the False Knight.
 * After version 1.2.2.1, the Watcher Knight's Back Roll move became glitched and no longer worked. This was fixed in version 1.5.68.11808.