Second Sentinel is one of Pharloom’s gilded automatons and a late‑game test of timing, mobility, and restraint in Hollow Knight: Silksong. This guide focuses on the practical sequence: how to assemble the Cogwork Heart, wake the Sentinel, make the Final Audience wish appear, find the boss arena in High Halls, and handle the moveset cleanly to earn the Reserve Bind tool.

What you need before you start

You can complete this quest in Act 2 or Act 3, but it’s gated by traversal and a bit of progression:

  • Faydown Cloak (double jump) to access both the hiding place in Cogwork Core and one of the bell rooms.
  • Clawline (grappling) to reach Cogheart puzzles comfortably and move through the Citadel routes that connect them.
  • Access to Choral Chambers and High Halls; expect additional progress flags (bench rests, key encounters, and a forum sequence) to help the wish appear later.
Tip: Don’t stress this thread while you’re first entering the Citadel. It slots in smoothly once your movement kit is fleshed out.

Assemble the Cogwork Heart (3 pieces)

The heart is split across three bell‑pattern rooms. Step on the floor switch to hear a short sequence, then ring the bells back in that order. The sequences lengthen across the three rounds in each room.

  • Whispering Vaults: Left‑side alcove below the stage area. The room is dim; move toward the edges so the end bells come into view before striking.
  • Choral Chambers: A room above the silk machine and opposite a Lost Flea room. If you haven’t opened nearby routes, reaching this from Songclave is straightforward.
  • Memorium: Through the upper reaches of the Choral Chambers (double jump required), then a small room to the right near the local map pickup. The bells are arranged in a ring.

Once you pick up the third piece, the Cogheart auto‑forms in your inventory. No crafting step is required.

Wake the automaton in Cogwork Core

From the Cogwork Core bench, head left into the lower machinery. Use double jump to reach a small platform above the entry, then break a pair of fragile walls to find a glass housing. Interact to place the Cogheart in the inert Sentinel’s chest.

The Sentinel will awaken, speak its duty, and depart to patrol the Citadel.

Make the Final Audience wish appear

Next, you need to bump into the Sentinel as it fights hostiles around the Citadel. These encounters tend to spawn in the long, horizontal corridors of the Choral Chambers (including both sides of the Cogwork Dancers arena, the hallway above Whiteward, and the spans near the spa terminal). Help clean up the skirmish, then move on.

  • Common trigger: Encounter the Sentinel in combat at least twice, rest at a bench, then check the Songclave wish wall for Final Audience.
  • If it doesn’t show: Keep roaming those longer corridors for further skirmishes, rest again, and recheck. Some runs only posted the wish after additional Citadel progress (e.g., finishing a forum fight, acquiring a conductor melody) alongside the two skirmishes.
Note: This thread isn’t missable. If you skipped it in Act 2, you can still trigger it in Act 3.

Where to duel the Second Sentinel

Accept Final Audience at Songclave, then travel to High Halls. From the local bench, climb one room up and proceed into a new side room to the right. The Sentinel will address you; speak to start the fight.

Moveset — what the animations tell you

The Sentinel’s kit is compact and readable, but it’s quick. Most hits come from dashing into unsafe space or attacking into a guard.

  • Chain thrusts: One blade pulled back, the other forward; the Sentinel lunges once, then often again. Jump, hover, or dash past the second step. There’s a small punish window when the sequence ends.
  • Spinning leap: Both blades are set parallel as the Sentinel jumps diagonally and spins. Dashing under the arc is consistent, with a short punish window on landing. At long range, it sometimes adds a diagonal energy burst afterward — keep moving.
  • Ground wave: Arms raise, then slam, sending an energy arc across the floor. Jump or double jump; a downward strike on the head is safe if you’re already above it.
  • Diagonal burst (air): A midair swing that throws a downward/diagonal blade of wind. Move toward the Sentinel’s front to slip past it.
  • X‑slash: A brief charge cues a large X‑shaped light slash that pops after a beat. Back off and stand between the arms of the X.
  • Guard counter: The Sentinel crosses blades and flashes; hitting it here triggers a fast stab flurry. Don’t feed the counter. Either disengage or bait it and step through to the back side before you swing.

Healing windows: After chain thrusts, after the spinning leap lands, and when you successfully bait a guard without striking. The fight is built around measured spacing — you’ll get tagged if you chase contact during its strings.

Simple game plan

  • Play past the tip. Dash through leap arcs and thrusts rather than retreating in a straight line.
  • Don’t swing into the flashing guard. If you accidentally do, immediately dash clear — the counter starts fast.
  • Use downward strikes to punish ground waves and certain landings, then reset to midrange.
  • Maintain vertical options. Hover and double jump keep you clear of floor arcs and let you gap‑close without eating stray thrusts.

If you prefer tools that work while you reposition, autonomous damage and pre‑placed bursts are effective while the Sentinel traverses the arena. Keep your defensive slot flexible for runs where healing opportunities are scarce.

Reward: Reserve Bind, and what it actually does

Defeating the Sentinel grants Reserve Bind, a blue tool that stores one bind’s worth of silk separately from your spool. You can heal once from this reserve even if your main silk is empty, and it refills at benches. Treat it as an emergency button for bosses with tight healing windows.

After the duel, the Sentinel resumes its duty around the Citadel. You may see it join fights in familiar corridors later on.

Quick checklist

  • Collect all three Cogheart Pieces (Whispering Vaults, Choral Chambers, Memorium).
  • Wake the Sentinel in Cogwork Core (double jump up, break two walls, place the heart).
  • Find it fighting in long Choral Chambers corridors at least twice, rest, then check Songclave.
  • Accept Final Audience, head to High Halls, enter the side room near the upper bench, and start the duel.
  • Win the fight to receive Reserve Bind.

If the wish won’t post

  • Re‑encounter the Sentinel in different long corridors in the Choral Chambers.
  • Always rest at a bench before checking the wish wall again.
  • Advance other Citadel threads (a forum fight, melody milestones), then repeat the encounter‑and‑rest loop.

Key takeaway: the quest hinges on three steps in order — assemble the heart, wake the Sentinel, then log real encounters in the Citadel before you’ll be invited to the duel. Once you’re in the arena, respect the guard flash, pass through the big movement arcs, and the fight opens up quickly.