You now have the key to unlock Lyhe Ghiah and must face the faerie king Titania.
How to Unlock
The Dancing Plague, an 8-player trial, is unlocked by the level 73 Main Scenario Quest Acht-la Ormh Inn.
First Phase
Bright Sabbath damages all players.
Phantom Rune will either attack in a circle centered on the boss or will attack in a donut, with a small safe area under the boss. Stay somewhat close to the boss so you can quickly move to the safe area after the attack marker appears.
Divination Rune is a cone attack in the direction that the boss is facing. The player highest on the enmity list should keep the boss facing away from the other players, and other players should always stay behind the boss.
Mist Rune places four puddles on the ground, each with a countdown timer above it. Make sure that there is at least one player in every puddle before the countdown finishes. Puddles with no players in them at the end of the countdown will turn into Spirit of Dew enemies that you will have to destroy.
Flame Rune will target a random player with a stack marker. The marked player should stand in a puddle (if there are any remaining) to receive a Flame Resistance Up status, and the other players should stand in the puddle the marked player to reduce the damage of the attack.
Midsummer Night's Dream will transform the area into a forest, signalling the start of the second phase.
Second Phase
Growth Rune will place a star-shaped marker in a random location. Vines will grow from where the star marker was, as indicated by the arrows pointing out of the points of the star. Players should look for the points of the star, then quickly move out of the path of the lines indicated by the points of the star. Players who stand on the vines will be trapped there by the Bind status until the vines disappear and will also be afflicted with Bleeding status. These statuses cannot be healed with Esuna.
Frost Rune marks the area with circle markers. One marker will be in the center, and the rest will form one by one in a circle around the edge. Each of these circles will attack in the order that they appeared. Stand next to the first of the edge circles that appeared, such that you are not standing in a circle marker until the final circle marker appears. When these circle attacks begin exploding, all players will be marked with Uplift, a circle attack that follows each player. Players will need to move into the areas where the unmoving circle markers have disappeared, and spread apart from each other to avoid overlapping other players with their circles. Be sure to minimize your own movement to help give other players a chance to find a safe spot.
Three additional enemies will appear: Mustardseed, Peaseblossom, and Puck. These enemies must be defeated as quickly as possible. The tanks should make sure to attack these enemies to prevent them from attacking other players. The tanks can use moves such as Provoke (available to all tank classes), Shield Lob (Gladiator/Paladin), Tomahawk (Marauder/Warrior), Unmend (Dark Knight), and Lightning Shot (Gunbreaker) to ensure that these enemies focus on them and not on other players.
After you defeat these enemies, much larger versions of the enemies will appear at three of the edges of the area. As before, the tanks should ensure that these enemies are focusing on them and not on the other players. Players should focus on defeating them one at a time. If you do not defeat all three before Titania's Power gauge is full, the party will be defeated and will have to start over from the beginning.
Throughout this phase, Puck will sometimes place a knockback circle marker in the middle of the area. Players should avoid standing in the circle itself, but can stand close to it to prepare for the knockback. Mustardseed will attack with Leafstorm, which places multiple cone attack markers on the area, while at the same time, Peaseblossom will target all players with Peasebomb, marking players with very large circle attack markers that follow the players. Carefully spread out while standing in a safe area between the cone attack markers.
A DPS player should use Limit Break on these enemies as soon as the three Limit Break gauges have filled. The gauge will become full during this part of the battle, and it is meant to be used at this time.
After you have defeated Mustardseed, Peaseblossom, and Puck, Titania will attack with Being Mortal. The higher Titania's Power gauge, the stronger the Being Mortal attack will be, and you will not survive if it reached 100.
Third Phase
During the third phase of the battle, Titania will use attacks that you have seen before. The Growth Rune attack will now place two star-shaped markers in the area, so be careful to avoid standing in line with the points of either of the stars. Phantom Rune will now alternate, so it will either be a donut attack followed by a circle attack centered on the boss, or vice versa, so after the first part of the attack, be ready to move to the next safe area.
Completing the Quest
Defeating the boss will complete one of the quest objectives for the Main Scenario Quest The Dancing Plague. There will be a cutscene. This one is important, so it is recommended to watch it either now or via the Unending Journey in an inn room. (Main Scenario 1 > Shadowbringers Main Scenario Quests > Acht-la Ormh Inn > Cutscenes 3 and 4.)