Calyx pits you against a mechanical guardian forged from Sphene's memories of Zelenia, the second-in-command of the royal knights.
How to Unlock
Recollection, an 8-player trial, is unlocked by the level 100 Main Scenario Quest Descent to the Foundation.
First Phase
Alexandrian Thunder IV is a circle attack centered on the boss followed by a donut attack, a donut attack followed by a circle attack centered on the boss.
Shock targets each player with a circle that follows them, then there is a countdown. Go to the edge of the area, then as soon as the countdown ends, step away from the circle, because each one will do a repeated attack.
Power Break hits the side of the room that the sword is pointing at.
When the boss casts Holy Hazard, two cone attack markers will appear from the boss, followed by two cone attack markers in different locations coming from the boss. Stand in a safe location to avoid getting hit by the first cone attacks, then move to one of the safe locations for the second cone attacks.
Specter of the Lost is a cone attack on both tanks. Any players in the path of the cone attacks will take damage.
Thunder Slash is a donut followed by a circle or a circle followed by a donut, also accompanied by cone attacks that occur in the order that the attack markers appear. While dodging the donut and circle, stand on one of the last cones to appear, then as soon as one of the other cone attacks has occurred, step into the location where it occurred.
Eventually, there will be a knockback attack. Stay near the boss to avoid getting knocked into the unsafe area around the edge. This is followed by a mid-battle cutscene, indicating the start of the second phase.
Second Phase
Throughout this phase, the space under the boss will become unsafe, so avoid the center of the area.
Roseblood Bloom places cone markers in certain locations, and circle markers will also appear in certain locations. Don't stand on these cone markers or circle markers.
The next time the boss casts Roseblood Bloom, she will also cast Power Break, so you need to avoid the unsafe side of the room while also avoiding standing on the cone and circle markers.
When the boss casts Shock, move your circle to the edge like before. This is followed by Stock Break, a multi-hit attack that targets a random player with a stack marker. Unmarked players should stack together with the marked player to reduce the damage of the attack, and stay together until the attack stops.
This time, when the boss casts Roseblood Bloom, she also casts Roseblood Drop, which makes a sphere appear in the outside of the area and float to a random location. It will activate the cone in the location where it stops, so make sure to avoid being in the path of the cone that was activated, because an attack will occur there at the same time that the other cone attacks go off. This is also paired with circle attacks and Power Break as before.
The next time the boss casts Roseblood Bloom, she will also cast Holy Hazard, so you will have to stand in the safe zone for the first cone attacks, then move to the next safe zone after the first attacks go off, while also avoiding the other cone and circle attacks.
Valorous Ascension places two curved lines at one edge of the area, followed by another two curved lines next to the first. The first ones that appeared will do line attacks, then the next ones will do line attacks. Dodge the first line attacks, but the boss will then cast Shock, so you will have to place your Shock circles on the edges of the area while also avoiding the line attacks. Right after the Shock circle countdown ends, the boss will cast Power Break, so move to the safe side of the area.
Thorned Catharsis damages all players.
The boss will cast Roseblood Bloom paired with Alexandrian Thunder, so you will have to dodge a donut attack followed by a circle, or circle attack followed by a donut, at the same time as avoiding standing on the cones and circles.
Completing the Quest
Defeating the boss will complete one of the quest objectives for the Main Scenario Quest Descent to the Foundation.