The Solus Heart is a hidden boss. You cannot reach it on a normal run. The access route requires defeating Solus Wing first, then completing a specific item crafting process in the Computational Exchange hidden realm.
Reach Conduit Canyon (Stage 4, AC DLC path). Use Sentry Keys to hack the barrier and decrypt the encrypted teleporter. Defeat the Solus Control Unit and Alloy Hunter.
Take the portal to Solutional Haunt (Stage 5, AC DLC). Drop down the massive tube and defeat Solus Wing. Pick up the Encrypted Cerebellum it drops.
Enter the portal through Solus Wing's eye. This takes you to the Hidden Realm: Computational Exchange.
In Computational Exchange, find CHEF behind the translucent glitchy wall. Give CHEF the Encrypted Cerebellum plus one of: Sentry Key, Encrusted Key, Rusted Key, Empathy Cores, Orphaned Core, or Prison Matrix.
CHEF combines the items into an Exposed Cerebellum. Give it to the large Solus unit near CHEF's kitchenette. A Decrypted Portal opens.
Enter the portal to reach Neural Sanctum and fight the Solus Heart.
You need a key item to give CHEF alongside the Encrypted Cerebellum. Sentry Key is the most common. Hold one back when clearing Conduit Canyon rather than spending all of them on the barrier terminals.
Solus Heart is essentially stationary with devastating ranged attacks. The cube arena floor is part of the fight - laser sweeps destroy cubes and collapse sections, shrinking your safe zone.
Dashes around the arena firing destructible red orbs that home toward the target after a short delay. Dodge laterally or destroy the orbs before they detonate.
Fires barrages of destructible white and blue projectiles. Both types activate most on-kill items (Gasoline, Topaz Brooch, Berzerker's Pauldron) when destroyed, making proc-chain builds extremely effective.
Summons pillars of white lasers that sweep through the arena at very high tick rate. Lasers destroy any cubes they pass through. These deal damage extremely fast - dodge immediately, even if it means dropping to the lower floor briefly.
Becomes invincible and charges a full-arena slam hitting everywhere except the outer edges. The cube floor collapses. Creates two columns of laser pillars sweeping each half, then fires barrages from all previous attacks.
Laser pillars deal damage at an extremely high tick rate. Getting caught in one removes health faster than almost any other attack in the game. Drop to the lower floor and briefly lose items if that's what it takes to avoid them. The wiki explicitly recommends this trade-off.
Once Solus Heart's HP reaches zero it stops fighting and makes an offering. You have a choice - and both paths unlock different AC DLC skins, but only for specific base game survivors.
Interact with Solus Heart. The run ends immediately. Result shows as "Decompiled into the Collective". Awards 5 Lunar Coins to all players. Unlocks Accept/Decompile skins for: Bandit, Artificer, REX, Loader, Captain.
Continue attacking until it dies. The run continues. Drops a random Legendary item. Unlocks Purge skins for: Commando, Huntress, MUL-T, Engineer, Mercenary, Acrid.
It depends entirely on your survivor. If you're playing Bandit, Artificer, REX, Loader, or Captain, accept. If you're playing Commando, Huntress, MUL-T, Engineer, Mercenary, or Acrid, reject. For any other survivor (including all SotS and AC characters) neither option unlocks a skin, so reject and take the Legendary item drop.
Solus Heart is stationary, making positioning straightforward, but its attacks are among the most punishing in the game. Mobility and the ability to stay out of laser sweeps determine the fight.
Stay mobile at all times. The white and blue projectile barrages are destructible - shoot them down and your on-kill items will chain-proc constantly. Save your hardest burst for when the arena is clear. When laser sweeps activate, immediately move perpendicular to the sweep direction or drop to the lower floor.
Destroy the projectiles. Both white and blue projectiles activate on-kill items when destroyed. If you have Gasoline, Ukulele, Will-o'-the-wisp, Topaz Brooch, or similar items, firing into the projectile barrages triggers massive chain procs. This is one of the most effective damage strategies for this fight.
Watch the cube glow. Cubes turn red before Solus Heart's attacks destroy them. This is your cue to reposition away from those sections before the floor collapses.
The outer edge is safe during the final phase. When Solus Heart's HP hits zero, it charges a full-arena slam that hits everything except the outer edges. Run to the edge the moment you see this begin.
Build for ranged burst. Solus Heart is nearly stationary. Railgunner, Artificer, and Bandit all excel here because they can burst from range during attack windows and reposition quickly when laser sweeps come.
Mobility items are critical. Hopoo Feathers, Wax Quail, and Goat's Hoof all help dodge the laser sweeps. The fight strongly rewards vertical and horizontal mobility.
Stationary boss with high-damage AoE attacks. Ranged survivors with mobility have the clearest advantage. Proc-chain builds are especially strong due to the destructible projectiles.
Solus Heart is essentially stationary, making it the ideal target for Railgunner's XQR Smart Round System. The destructible projectiles proc kill items when shot down. Supercharge deals massive burst and the entire fight can be controlled from range, making laser sweeps easy to sidestep.
Grapple hook mobility lets Loader reposition instantly away from laser sweeps. High burst on a stationary target. Barrier generation from hits helps sustain through the high-damage final phase. Strong across the entire fight.
Ion Surge flight avoids ground-level laser sweeps and the final phase arena slam (outer edges are safe, flight gives freedom). Charged Nano-Bomb and Plasma Bolt burst are effective on a stationary target. Flame barrier blocks red orbs.
Smokebomb grants brief invincibility that can be timed to avoid the final phase arena slam. Backstab crits punish the long attack animations. Good burst DPS on a mostly stationary target. Lights Out reset gives very high single-target kill potential.
Strong sustain through Meditate that helps recover between burst attacks. Spirit Punch hits through the destructible projectiles, triggering on-kill effects. Sojourn mobility helps dodge laser sweeps.
Strong damage but must fight close to a boss that has extremely dangerous laser sweeps at close range. Eviscerate I-frames help but require careful timing. Experienced Mercenary players handle this well, but the laser pillars are punishing at melee range.
Slowest movement speed in the game makes dodging laser sweeps and the red orb barrages more difficult. High HP and 12 base armor provide tankiness. Nail gun/rebar alternating attack combo deals solid damage on a stationary target, but positioning is the challenge.
The Solus Heart is the true final boss of the Alloyed Collective DLC. It is a secret hidden boss accessed through a multi-step process after defeating the regular AC final boss, Solus Wing. It is fought in the Neural Sanctum hidden realm.
Defeat Solus Wing and collect the Encrypted Cerebellum it drops. Enter the portal through Solus Wing's eye to reach Computational Exchange. Find CHEF and give him the Encrypted Cerebellum plus one key item (Sentry Key, Encrusted Key, Rusted Key, Empathy Cores, Orphaned Core, or Prison Matrix). Take the Exposed Cerebellum CHEF gives you to the large Solus unit. Enter the Decrypted Portal to Neural Sanctum.
Both choices unlock different AC DLC skins for base game survivors. Accepting ends the run immediately and awards 5 Lunar Coins. Rejecting lets the run continue and drops a random Legendary item. If your character is Bandit, Artificer, REX, Loader, or Captain, accept. If your character is Commando, Huntress, MUL-T, Engineer, Mercenary, or Acrid, reject. Other characters have no AC skin to unlock either way.
If you reject the offering and kill it, Solus Heart drops one random Legendary item. Accepting the offer ends the run without a drop but awards 5 Lunar Coins instead.
Solus Heart's laser pillar sweeps deal damage at a very fast tick rate. Even brief contact removes significant health. They also destroy the cube floor when they sweep through it, shrinking the arena. The wiki recommends dodging them at all costs, including dropping to the lower floor temporarily and having items disabled briefly rather than taking the laser hit.
Yes. Both white and blue projectiles are destructible and trigger most on-kill items when destroyed. Items like Gasoline, Topaz Brooch, Berzerker's Pauldron, Ukulele, and Will-o'-the-wisp all proc when you destroy these projectiles. Proc-chain builds become very powerful in this fight because of this.
