Part 4: Underground Alchemy Foundry

Step 1: Breaching the Steam Boiler Hall & Flame Cannon Upgrade

Descend the freight elevator into the Boiler Hall. Two Steam Automatons guard the blast doors. Equip your Ominous Greatsword to crack their bronze armor plates, then activate your Flame Cannon to ignite their exposed fuel reservoirs for an instant detonation.

MISSABLEPrototype Alchemical Stabilizer: In the western laboratory wing (Room B-04), use your Shadow Hook to swing onto the suspended cage above the molten vat. Inside the iron safe lies the Prototype Alchemical Stabilizer. Handing this to Physician Sui later stabilizes Soul's heart, unlocking the true "Eternal Blade" narrative ending. If missed, this room is permanently flooded with lava in Part 5.

Step 2: Steam Pressure Valve Calibration Puzzle

The primary blast gate requires balancing three pneumatic pressure gauges to 120 PSI before the emergency vents vent lethal steam:

• Turn the Red Pressure Wheel (Left) 3 clicks clockwise.
• Turn the Blue Condenser Valve (Center) 1 click counter-clockwise.
• Pull the Overheat Emergency Lever (Right) once.

The hydraulic pressure will equalize, draining the central elevator platform and granting you Heart Shard #4 (+5% Max HP).

Step 3: Boss Duel — The Clockwork Puppet General

Ride the grand gear lift down into the subterranean foundry arena. The Clockwork Puppet General, a massive four-armed automaton driven by clockwork gears and wielding dual halberds and rotary buzzsaws, drops onto the steel grating.

TACTICS WARNING: Click to Reveal Detailed Boss Tactics & Weaknesses

Boss Profile: Heavy clockwork mech with high armor resistance and rotational blade attacks.

• Phase 1: The General swings twin halberds in alternating sweeps. Stand close to his left knee—his horizontal swings miss, allowing you to land uninterrupted Dual Blade strikes on his vulnerable hydraulic knee joints.
• Buzzsaw Rampage: When he revs his lower arms and spins toward you like a tornado, retreat and fire the Flame Cannon. Incendiary fire overheats his internal engine, causing him to vent steam and kneel motionless for 5 seconds.
• Phase 2 (Overclocked Core): At 30% HP, the General rips open his chest to expose his glowing core. Use the Shadow Grapple to slingshot directly into his core and execute a devastating aerial plunge strike.

MAJOR STORY SPOILER: Click to Reveal Plot & Narrative Details

When the General collapses, its control module reveals audio logs between The Order's elders and the Grand Preceptor. Soul's 66-day heart was engineered as a living key designed to unlock the Netherworld Seal atop the Tower of Thousand Blades, sacrificing Soul to grant the Preceptor immortality.