Keep Construct

Enrage: 10 minutes. When Enraged, Keep Construct will deal 200% damage.
Tank: Toughness
Keep Construct heavily favors builds that deal high power damage due to its low Toughness compared to other raid bosses and its short burst phases. Additionally, adds will spawn that must be quickly cleaved, further biasing the encounter towards burstier classes. Power Bladesworns, Soulbeasts, and Catalysts are all common on this boss due to fitting exactly this profile, but any power DPS build is a viable pick.
While Keep Construct requires a Toughness tank, tanking is straightforward and can be done comfortably by most support builds.
Enabling the mote outside the arena activates the Down, Down, Downed achievement, which is Keep Construct’s “Challenge Mode” (with the associated extra weekly rewards).
The only difference with the achievement enabled is that the playable space is permanently reduced during the encounter. This does not change the approach to the fight in any way, so the following all still applies.
The encounter begins when players approach the center of the arena. The tank should remain against the edge and allow Keep Construct to approach them.
Keep Construct starts the fight with two stacks of Xera's Embrace
Projection
Known as: statue, adds
Two statues will light up, one on each half of the arena; the tank should bring Keep Construct to the nearest lit statue.
Projections will spawn from each lit statue and will fixate on two random players. These fixated players have two tasks: luring each projection on top of Keep Construct and keeping the two Projections from getting close to one another.
When a Projection dies near Keep Construct, it will remove one stack of Xera's Embrace
If two Projections get close to one another, they will stop all other movement to merge, becoming a bright red Insidious Projection. The Insidious Projection does more damage and has a frontal smash attack that strips boons from the squad. Many groups will call for a reset if a merge occurs, so this situation should be avoided at all cost.
Generally, the close fixate should stand on the opposite side of Keep Construct from their Projection to make their Projection walk into Keep Construct and into the squad’s cleave. The far fixate should keep an eye on the first Projection’s health, pulling their Projection slightly off group if the Projections are at risk of merging. Otherwise, they can walk through Keep Construct to pull their fixate in as well.
Whenever the boss is free to move, it can choose between one of the following three mechanics at random. All three mechanics will be cancelled if the boss’s breakbar is active and is broken in time.
Xera’s Fury
Known as: Spread
Every player will gain a light orange circle under their feet. When these detonate, each circle will damage any players standing within them for 20% of their maximum health. All players except for the fixates and the tank should spread for this mechanic.
Fixates should stay on Keep Construct to ensure that the Projections will not die far from Keep Construct. Additionally, if a Projection is pulled far from Keep Construct, squads will often struggle to re-target and kill it, making an Insidious Projection merge much more likely.
Attuned Phantasms
Phantasms will spawn around the arena with red and
white markers over their heads. If these phantasms are not killed in time, Keep Construct will do a massive attack, typically wiping the entire group.
Players will also gain the same red or white markers over their head, indicating which phantasms they can damage.
Hail of Fury
In addition to the two random mechanics above, when under 33% HP Keep Construct will occasionally float into the sky, dropping rocks onto the arena. The squad should treat this mechanic as though Keep Construct hasn’t moved—killing Projections where Keep Construct floated up from will still strip stacks of Xera's Embrace
Exposed Core Phase
Once Keep Construct’s bar has been broken, Keep Construct will retreat and three green circles will spawn on the arena. Each circle must have at least two players in it by detonation or the squad will wipe.
Groups will often assign supports to two of the circles while keeping all DPS players on the remaining circle. By assigning all DPS to one circle, the fixate can pull the Projection to the DPS group, allowing them to quickly kill it.
Remember if a support from the other two circles are fixated, one DPS player should react and switch places with the fixated Support, allowing them to pull the Projection to the DPS’s circle. If you don’t know who should switch places with the fixated support, it’s always… you.
After detonation, a pink Construct Core will appear in the middle of the arena. The arena will also gain a pink border and five Ley Rifts along the edge.
Pushing the Core
Known as: orb, pushing
For each Ley Rift the Construct Core passes through during this phase, Keep Construct will gain a stack of the Compromised
Keep Construct will respawn when the Orb is either pushed into the border of the arena or when small Retriever Projections steal the Orb.
The Core can be pushed by any attack, but dedicated crowd control such as pushes, pulls, and launches will work as well. One player should be assigned to handle this mechanic, but other players can help if requested. Often, a Druid will be designated as the pusher; this player should remember to disable their pet’s attacks so they don’t erratically push the orb.
The squad should aim to push through enough rifts to phase Keep Construct during the burn phase. Keep Construct phases at 66% and 33% HP remaining, so if he is near that health when the Core is exposed, only one rift should be necessary. If his health is far from these thresholds, more rifts should be captured: five rifts is always the safest bet, but groups with good damage can usually manage with three (or even less).
If at least one rift was captured when the Core is retrieved, when he respawns Keep Construct will be Stunned
Compromised
Xera's Embrace
Note: If Keep Construct is very close to one of the HP thresholds when leaving the burn phase, it’s often better to ignore the breakbar if it appears and instead focus on getting his health over the line, since breaking the bar forces the squad to go through the entire Exposed Core phase again.
Magic Blast
At 66% and 33% HP remaining, Keep Construct will become invulnerable and will start channeling Magic Blast, a massive explosion that affects the entire squad. Players will gain red or white markers over their head, and red and white balls will move towards Keep Construct. Everyone should block balls matching their marker from reaching Keep Construct.
Each ball that reaches Keep Construct will give him a stack of Magic Blast Intensity
Protection
Players will take a small amount of damage when capturing each orb. One common approach to counter this has a Druid drop a Water Spirit
Typically, players should aim to spread out from other players with the same colored marker. Trust your teammates—you don’t need to run across Keep Construct to capture their orbs! Instead, focus on your section.
When the boss starts moving the group should restack to heal up from the blast and prepare for Phantasmal Blades.
Condition cleanses such as Glyph of the Stars
At the end of this attack, two statues will light up to spawn Projections. The entire squad should run to one of them (usually the one on the eastern side), as Keep Construct will target a random player to leap on. The squad can Dodge
Aegis
Stability