Finding and Utilizing the Apostate Key in Hollow Knight: Silksong

The Apostate Key is a vital item in Hollow Knight: Silksong, serving as a crucial unlockable for both story progression and optional content within the ominous region known as The Slab. Unlike the Indolent and Heretic Keys, which facilitate initial escape and gear retrieval from The Slab, the Apostate Key is located in a distant area of Pharloom, requiring specific abilities and careful navigation to acquire. Its elusive nature contributes to Silksong's non-linear, Metroidvania-style exploration, often prompting players to revisit areas with newfound powers.

What is the Apostate Key?

The Key of Apostate is a Key Item designed to unlock specific cells and passages within The Slab region. Obtaining it grants Hornet easier access to previously inaccessible areas, allowing for deeper exploration, engagement with challenging encounters, and the discovery of valuable upgrades. It is particularly essential for unlocking the latter half of The Slab, which might otherwise remain a mystery to players.

How to Find the Apostate Key

Locating the Apostate Key is a significant undertaking, as it is not found within The Slab itself but in the Putrified Ducts region, situated in the top-right corner of Pharloom's world map. Successfully reaching this remote area and retrieving the key depends on having specific movement abilities.

Prerequisites for Discovery

Before embarking on the hunt for the Apostate Key, Hornet must possess the following abilities:

• Faydown Cloak (Double Jump): Acquired by ascending Mount Fay, this ability is essential for reaching higher ledges and traversing vertical sections en route to the Putrified Ducts.
• Clawline / Cling Grip / Swift Step: These abilities, allowing for grappling, wall-clinging, and extended dashes, are crucial for navigating treacherous environments and overcoming gaps.

Accessing the Putrified Ducts

Players have two primary routes to reach the Putrified Ducts, each offering a distinct journey:

Via Memorium (Upper Route)

This route begins in the Songclave area and generally involves ascending:

1. Initiate from Songclave: Head towards the first shrine and follow the path leading to the Cogwork Dancers boss.
2. Ascend to Memorium: Along this path, look for a point where Hornet can jump up into the Memorium area. Alternatively, some sources describe a secret opening in the ceiling of one of the Choral Chambers' rooms, leading to Memorium's upper level.
3. Traverse Memorium: Proceed to the far right of Memorium. This path leads outside, across the top of a bridge where bats may attack. This location is also notable for featuring the merchant Jubilana in "The Lost Merchant" quest.
4. Enter Putrified Ducts: At the far end of this outdoor section, jump up to find the entrance to the Putrified Ducts. Another method involves climbing a wall and destroying a breakable rock at the end of Memorium to gain access.

Via Bilewater (Lower Route)

This alternative route through Bilewater often involves a boss encounter:

1. Defeat Groal the Great: One method is to defeat Groal the Great at the summit of Bilewater, which subsequently opens a shortcut leading towards the Putrified Ducts.
2. Ascend from Bilewater's Bellway: Starting from the Bellway in Bilewater, continuously climb using the Double Jump until reaching Shakra's location.
3. Navigate Challenging Terrain: Platform upwards by clinging to walls and evading spikes to pass through a right-side door. The subsequent room features enemies and vertical platforms. Use Clawline to shoot green bulbs and cross to the other side, then climb higher, shoot an enemy, and land on a platform before heading right through another door.
4. Utilize Clawline and Double Jump: Continue into the area, climbing higher and using Clawline to fly onto platforms. Pass hanging enemies into the next room, then jump across temporary platforms while avoiding water. Glide down a tunnel, climb the next, and meticulously avoid enemy attacks and traps to Double Jump to a higher platform, then move right.
5. Final Ascent: In the subsequent area, a combination of Double Jump and Clawline is necessary to climb further, staying to the left and using green bulbs to gain height. Proceed through the first door on the left.
6. Bench Checkpoint: If approaching from the left, a nearby bench can serve as a convenient checkpoint before reaching the key's immediate vicinity.

Retrieving the Key within Putrified Ducts

Once inside the Putrified Ducts, regardless of the entry route, the final steps to obtaining the key are as follows:

1. Locate the Main Shaft: Navigate through the ducts to find the main vertical shaft.
2. Descend and Traverse: Go all the way down to the bottom of this shaft, then proceed left.
3. Enter the Dark Tunnel: Hop up into a dark tunnel that continues to the left. Be wary of a giant enemy residing in this passage.
4. Claim the Key: At the far end of this corridor, the Apostate Key is found inside a smashable cage or a glowing object. Destroy it to claim the key. This section of the Putrified Ducts is also where players can initiate the "Broodfeast" quest.

It is worth noting that Bilewater contains hazardous contaminated water infested with Muckmaggots; equipping the Wreath of Purity charm is highly recommended for safe passage.

Using the Apostate Key in The Slab

With the Apostate Key in hand, Hornet can return to The Slab to unlock two distinct locations, each offering significant rewards or progression:

Unlocking New Areas and Challenges

One of the Apostate Key's primary uses is to open a new area within The Slab, often leading to a challenging boss encounter.

• Location: This lock is typically found at the bottom of a main shaft within The Slab, often close to a bench and fast travel point (Bellway).
• Path: From The Slab Bellway, ascend and turn right to reach the locked door. After passing through, going up first reveals a shortcut, then sliding down. Proceed right into a room with lore tablets. Look up and use Double Jump and Clawline to climb a tunnel, entering a door at the end. Continuing left leads to the Heretic Lock.
• Reward: Breaking chains in an eerie chamber beyond this door will initiate a battle with a major foe: The First Sinner. Defeating this boss rewards Hornet with the Rune Rage silk skill, a powerful combat ability.

Solving the Mask Shard Puzzle

The second application of the Apostate Key reveals a complex platforming puzzle culminating in a valuable health upgrade.

• Location: This lock is situated at the top-right portion of The Slab's central shaft.
• Puzzle Sequence:
  1. Press a nearby button four times to spawn four bladed wheels.
  2. Double Jump onto the platform above.
  3. Wait for a wheel to approach, then use it as a temporary platform to jump higher and cling to the left wall.
  4. Climb higher to jump onto two wheels and cling to the right wall.
  5. Wait for one of the wheels to align with a ledge, then jump from it to reach a final platform.
  6. Reward: Grab the Mask Shard located on this platform, contributing to a health upgrade for Hornet. This traversal segment can be quite tricky, requiring precise timing and movement with the spinning bladed wheels.

The Apostate Key, while challenging to obtain due to its remote location and prerequisite abilities, is indispensable for fully exploring The Slab and securing valuable rewards that enhance Hornet's capabilities in her journey through Pharloom.