Dancer of the Boreal Valley

The Dancer of the Boreal Valley is a boss in Dark Souls III.

Description
The Dancer is a towering, lanky being that resemble more to her master, Pontiff Sulyvahn, than the other beastly armored knights from Irithyll, like Vordt. She stands upright instead of crawling on all four and shambles with deceivingly slow steps. This unusual gait, paired with the caustic dark ooze (very similar to the liquid that exudes from Knight Artorias) that drips from her body whilst warping into the cathedral, may imply a connection with the Abyss.

Location
Found in the High Wall of Lothric, in the cathedral where Priestess Emma resides. Requires that the player has already defeated the first three Lords of Cinder: the Abyss Watchers, Aldrich and Yhorm.

After the third Lord of Cinder has been defeated, a cutscene will play with Emma summoning the Ashen One to the cathedral. Once there, she will bestow them the Basin of Vows. Walking up to the statue of the beheading knight behind her with it in possession will make the Dancer reveal herself and initiate the boss fight.

Alternatively, the player may kill Emma at any time during the game, loot the basin from her body and approach the statue to commence the battle.

Strategy
Since the room where this boss fight takes place is arguably small for fighting a boss of this nature, the player may opt in destroying most furniture inside beforehand, in order to remove most obstacles that may hinder movement in precarious moments during the battle.

The columns around the chapel, as well as the walls surrounding the niche where the statue of the beheading knight lies, can be set on fire by hitting them with a Fire source, like the torch. This may be performed prior to the battle in order to have a better light source during the encounter. The flames emitted by the columns are completely harmless to the player and they are only there for aesthetic purposes.

For the first phase of the fight, it is best to stay near her right leg so that her grab is easier to see (although it doesn't reach far, it can reach far around her left side, making it a bad idea to side roll). Boosting fire resistance with the Flame Stoneplate Ring or Red Bug Pellet may be a good idea but not required as it is in your best interest to avoid her attacks altogether. Using stamina reinforcers like the Grass Crest Shield, Chloranthy Ring, or Green Blossoms are a good idea, as it will allow you to roll more as her attacks can false combo and some have a delay that can mess up your timing and would require two or three rolls to avoid.

Around half health, she will bring out her other blade that does Magic damage and dual wield both, so she won't do her grab. The particle effects may look they can damage, but they won't so it is a prime time to punish, especially with a bleed build. Afterward, she most likely will start twirling. At the end of her second phase punish, you will want to stay behind her and wait until she does a roundhouse twirl. For the second phase, it is actually a better idea to stay right in her rather then attacking her back side, as it will be easier to read her attacks and a lot of her second phase attacks are twirls that can easily catch you.

Alternative method

If the player has already defeated the Sword Master in Firelink Shrine, his summon sign will appear on the other side of the cathedral's courtyard, just outside of Vordt's boss room. The player may summon him and bring him to the cathedral, kill Emma, loot the basin from her body and commence the boss fight. If early in the game, the Dancer may kill the player with just one hit, so they should stay as far as possible from the fight and let the Sword Master deal with her.

The Sword Master will undoubtedly die the first time; once this happens, the player must exit the game immediately. On continue, they will appear outside of the cathedral, where they can make way to summon the Sword Master a second time and bring him to confront the Dancer once more. This time around, however, he will have have a broken hitbox and will only take damage from the debuff inflicted by his own weapon, the Chaos Blade, being capable of defeating the Dancer all by himself. Additionally, the Dancer won't be able to perform her grab attack on him anymore. The Sword Master will heal himself every time he is at approximately half health and will continue to fight the Dancer until she dies (occasionally bleeding her out with his Chaos Blade).

Once this has been accomplished, the player will gain access to two advanced areas in the game: Lothric Castle and the Consumed King's Garden, where they will find advanced loot and be able to level up faster. Additionally, this is a quick way to net near 50,000 souls (if wearing the Covetous Silver Serpent Ring) and the Dancer's soul.


 * Note: This method can only be accomplished before defeating Vordt of the Boreal Valley. If he is killed beforehand, the Sword Master's summon sign will disappear from the area.

Trivia

 * In Irithyll of the Boreal Valley, several ghosts of long dead knights can be seen wandering along the city streets. Two unique ghosts in particular, one male and the other female, can be seen departing from the cathedral. They heavily resemble Vordt and the Dancer of the Boreal Valley, both of which served together under Pontiff Sulyvahn's command.
 * In the network test and early demos, the Dancer's name appeared as the "Dancer of the Frigid Valley".