Hollow Knight: Silksong, released on September 4, 2025, represents a massive leap in Metroidvania design. While the game's developer, Team Cherry, did not officially structure the experience into chapters or acts, the community has universally adopted the term "Act 3" to describe the definitive late-game shift following the "Silk and Soul" questline. Unlocking this phase is essential for players seeking the true ending and access to the Void-altered version of Pharloom.

Accessing Act 3 requires completing a series of intricate side quests, gathering specific late-game artifacts, and making a critical choice during the final boss encounter. This guide details every requirement to transition from the mid-game (Act 2) into the final, abyss-focused stage of Hornet’s journey.

Understanding the Structure of Pharloom

In the traditional progression of Silksong, players move from the lower regions like Moss Grotto and Deep Docks (Act 1) into the central hubs of Bellhart and Song Clave (Act 2). The transition to what players call Act 3 is not triggered by simple exploration but by a complex ritual that alters the save file itself.

It is important to clarify that reaching the final boss, Grand Mother Silk, and defeating her normally will result in a standard ending, often referred to as the "Bad" or "Incomplete" ending. To "unlock" Act 3, you must intervene in the binding process using the Silk and Soul quest items.

Core Prerequisites for Act 3

Before you can initiate the final quest, your progress must meet several milestones across Pharloom. If you have not met these conditions, the essential NPC, the Caretaker, will not provide the final mission.

Completion of Wish Boards

The Wish Boards in Pharloom serve as the primary quest system. To trigger the endgame, you must clear almost every objective on the boards in the following three settlements:

  • Bone Bottom: Focus on the initial repair quests and the delivery of Rosaries.
  • Bell Hart: Requires the completion of the mapping quests provided by Shakra and the clearing of the "Restoration of Bellhart" chain.
  • Song Clave: This is the most difficult board, requiring you to finish "Strengthening Song Clave" and several high-level combat bounties.

Note that regular quests contribute 1 full point toward your progression total, while Courier (delivery) quests count for 0.5 points. Our testing indicates that a minimum of 17 accumulated quest points is required to flag the "Silk and Soul" mission.

The Flea Caravan and Flea Topia

The flea-finding mechanic is more than a simple collectible hunt; it is tied directly to the world state. To unlock Act 3, you must rescue a minimum of 25 lost fleas out of the 30 scattered throughout the kingdom.

The caravan moves through three distinct phases:

  1. Phase 1: Moves from The Marrow to Greymoor after 5 fleas are rescued.
  2. Phase 2: Moves to the Blasted Steps near the Citadel after 15 fleas are rescued.
  3. Phase 3 (Flea Topia): Once you have 25 fleas and have discovered the Putrefied Ducts, the caravan will relocate to its final destination, Flea Topia. This relocation is a hard requirement for the endgame trigger.

Securing the Bell Home

After completing the Bellhart wish board, you must speak with the NPC Pavo. If all conditions are met, Pavo will grant you the Bell Home Key. Your home is located in the upper-left section of the main Bellhart chamber. While the home serves as a hub for customization, obtaining the key is the technical flag the game uses to recognize you as a "Master of Pharloom," which is necessary for the Caretaker’s dialogue to update.

Fixing the Cogwork Automaton

In the Cogwork Core area, you will find a deactivated automaton. You must bring three Cog Hearts (found in the Gilded Citadel) to restart it. After its activation, you must encounter the automaton again in the Memorium and the Citadel Spa. Only after these encounters will a final quest appear on the Song Clave board that allows you to "Fix the Second Sentinel," a vital step in preparing the trap for the final boss.

The Silk and Soul Questline

Once the prerequisites are met, fast travel to Song Clave and speak with the Caretaker. They will reveal an alternative method to deal with Grand Mother Silk—one that involves trapping the essence of the boss rather than Hornet sacrificing herself. This initiates the "Silk and Soul" quest, requiring four unique artifacts.

1. The Maiden’s Soul

This is the easiest item to acquire but requires returning to the very beginning of the game. Travel to Bone Bottom and head left past the initial spawn point. Speak with the Chapel Maid. As the first NPC you encountered, she holds the "Maiden’s Soul," representing the beginning of Hornet’s thread.

2. The Hermit’s Soul

The Bell Hermit, located beneath the fast travel station in Bell Hart, holds this artifact. Throughout the game, he acts as a cryptic observer. Once the quest is active, his dialogue changes, and he will relinquish the soul. If he does not, ensure you have purchased at least five different Bell Charms from various merchants, as this sometimes acts as a secondary trigger for his cooperation.

3. The Seeker’s Soul (Bile Water Region)

This is widely considered the most difficult requirement. You must travel to the Bile Water region, accessible via Sinner’s Road in Greymoor. This area is saturated with maggot-filled pools that inflict a unique debuff: your Silk meter and Health will drain at a rate of 10% per second while submerged.

To get the Seeker’s Soul:

  • Navigate to the top of the main central shaft in Bile Water.
  • Defeat the boss Gro Al the Great. Gro Al spits energy-draining globules that make the floor hazardous. We recommend using the "Winged Needle" tool to maintain air time during this fight.
  • Enter the hut to the left of the boss arena to claim the Seeker’s Soul.

4. The Snare Setter (Weavenest at La)

The Snare Setter is hidden in a secret sub-zone called Weavenest at La. To enter, you must stand before the ornate metal door in the eastern Moss Grotto and play your Needolin (the interaction prompt appears once the quest is active).

Inside the Weavenest:

  • Use the elevator to descend.
  • Look for a fake ceiling between the last light fixture and the water pool in the middle corridor.
  • Double jump upward to find a hidden altar containing the Snare Setter.

Unlocking Act 3: The Final Battle

With all four items in your inventory, return to the Caretaker in Song Clave. They will construct the "Great Snare." Now, you must head to the Cradle for the final encounter with Grand Mother Silk.

The Needolin Choice

Fight Grand Mother Silk as you normally would. The boss has three phases, with the third phase involving rapid-fire silk projectiles that cover the entire screen. Once her health bar is depleted, the boss will enter a staggered state.

Normally, you would see the prompt to "Bind." Do not select Bind. Instead, because you have the Silk and Soul items, a second prompt will appear: "Needolin."

Hold the button to play the Needolin. A cinematic will trigger showing the Great Snare being deployed, and instead of a peaceful resolution, the Void is unleashed from beneath Pharloom. The screen will fade to black, and you will be returned to the main menu.

Entering the Void-Altered Save

Upon returning to the main menu, look at your save slot. It will be covered in black, pulsing vines or threads. This is the final "requirement" to enter Act 3.

  • Click (or press the confirm button) on the blackened save slot repeatedly.
  • On the 5th or 6th click, the threads will snap, and the save will load.
  • You will wake up in a transformed version of Bone Bottom, officially marking the start of Act 3.

What Changes in Act 3?

Unlocking Act 3 isn't just a narrative milestone; it fundamentally changes the gameplay loop of Silksong.

The Abyssal Infection

The "Void" now permeates every region. Enemies you previously defeated are replaced with "Void-Touched" variants. These enemies have higher health pools and aggressive new attack patterns. For example, the standard Crawbugs in Moss Grotto now leave trails of void essence that damage Hornet on contact.

New Abilities and Upgrades

Act 3 allows you to upgrade your Needle beyond the standard "Pale Oil" limit. By collecting "Void Shards" from the new Abyssal mini-bosses, you can reach the final weapon tier. Additionally, certain areas that were previously blocked by "Shadow Walls" can now be bypassed using the "Shadow Dash" ability, which is only obtainable after the Act 3 transition.

The True Final Boss

Act 3 culminates in a journey to the very bottom of the map, below the Deep Docks, into an area simply called The Root of the Abyss. Here, the true final boss of the game awaits, offering the "True Ending" of Hollow Knight: Silksong.

Summary of Act 3 Requirements

To ensure you don't miss any steps, refer to this checklist:

Requirement Location Key Detail
Wish Board Points All Settlements Reach at least 17 points total.
Flea Caravan Flea Topia Rescue 25 fleas and find them in Putrefied Ducts.
Bell Home Key Bellhart Talk to Pavo after clearing the local board.
Silk and Soul Quest Song Clave Initiated by talking to the Caretaker.
Four Artifacts Pharloom Maiden's Soul, Hermit's Soul, Seeker's Soul, Snare Setter.
The Choice The Cradle Use "Needolin" instead of "Bind" on the final boss.

FAQ

Can I go back to the normal world after unlocking Act 3? No. Once you load the blackened save file, the world of Pharloom is permanently altered for that save. It is highly recommended to complete all standard exploration, such as finding every Mask Shard, before triggering the Act 3 cinematic.

Do I need to find all 30 fleas? No, only 25 are required to move the caravan to Flea Topia and trigger the endgame state. However, finding all 30 grants a powerful defensive charm that is very helpful against the Void-touched enemies in Act 3.

Is Act 3 required for the 100% completion achievement? Technically, the game allows for 112% completion. Reaching Act 3 is required to access the final 12%, which includes the Abyssal bosses and the true final weapon upgrade.

What happens if I accidentally click "Bind" instead of "Needolin"? You will get the standard ending and credits. However, after the credits, you can reload your save from the last bench before the boss and try again, provided you have the Silk and Soul items in your inventory.

Is the "Sea of Sorrow" expansion part of Act 3? According to the 2025 release notes, Sea of Sorrow is a separate free expansion scheduled for 2026. It is expected to add a new region reachable from the Deep Docks, but it is not a requirement for the base game's Act 3.

By following these steps, you will successfully transition into the darkest and most challenging portion of Hollow Knight: Silksong, uncovering the secrets of the Void and Hornet’s true destiny in the kingdom of Pharloom.