Hollow Knight: Silksong Infestation Operation

Infestation Operation is the short, targeted wish that removes Hornet’s witch curse during Rite of Rebirth. You’ll speak to Yarnaby in Greymoor, purchase Steel Spines from Crull and Benjin on Sinner’s Road, then return to Yarnaby to complete the cure and receive the Witch Crest.

Plan your route and prerequisites

Infestation Operation becomes available while Hornet is cursed by the Twisted Bud as part of the Rite of Rebirth. While cursed, healing, and many tools are disabled, so plan a clean route with minimal combat and precise platforming.

Start Rite of Rebirth by delivering the Twisted Bud to Greyroot (you’ll become cursed and relocate to the Chapel of the Witch). This sets the stage for meeting Yarnaby and beginning Infestation Operation.

Ensure you’ve activated the lift near Halfway Home in Greymoor. This creates a faster, safer path to Yarnaby while your kit is limited.

Carry enough Rosaries for the purchase. Expect to pay around 260 Rosaries for the Steel Spines; some patches or play states may show a different price. Bring at least 260 to avoid a second trip while cursed.

Equip traversal abilities that still function while cursed. Drifter’s Cloak (glide), Cling Grip (wall jump), and Clawline (grapple) streamline the Sinner’s Road jail climb. Faydown Cloak (double jump), if you have it, simplifies one tricky reach.

Start Infestation Operation (meet Yarnaby)

Yarnaby lives in the northwest of Greymoor, inside a locked Bellhome you can call open.

From Chapel of the Witch, work left through breakable bramble blocks until you exit the area. Use flowers to pogo upward sections and keep moving toward Bellhart, then into Greymoor.

In Greymoor, use the nearby lift up from Halfway Home, then climb into the upper-left quarter of the zone. Look for a locked Bellhome on a platformed ascent with cages and wheels in the background.

Call at the Bellhome’s door to prompt Yarnaby. Call again to enter, then speak with Yarnaby to start Infestation Operation. Your objective is to bring back Steel Spines from Crull and Benjin in Sinner’s Road.

Buy Steel Spines from Crull and Benjin (Sinner’s Road)

Crull and Benjin are found in Sinner’s Road’s jail section, in the upper-right corner of a vertical room reached via a short platforming chain.

Exit Yarnaby’s Bellhome and head east toward Sinner’s Road. Favor high paths and stable platforms to limit fights while cursed.

Enter the jail area and start climbing. Use hanging cages and ledges, chaining Drifter’s Cloak and Clawline to extend airtime and reduce missed jumps.

Near the top, a small gap requires a reach from a cage ledge. Time a pogo off a flying enemy or use Faydown Cloak to gain the height, then Cling Grip up the wall.

Cross the final gap by pogoing off the suspended spiked rings (strike once, then tap to bounce; keep rhythm to maintain height). Reach the far platform to enter Crull and Benjin’s room.

Speak to Crull and Benjin and purchase the Steel Spines. Prices vary by patch/state; budget 260 Rosaries to be safe.

Return to Yarnaby and cure the curse

With the Steel Spines in hand, a direct return finishes the job.

Retrace your route back to Greymoor. If you opened shortcuts during the climb, use them to reduce risk while cursed.

Call at Yarnaby’s Bellhome, then speak to Yarnaby to complete Infestation Operation. The witch curse is lifted and you receive the Witch Crest.

Recommended abilities and route tips

Drifter’s Cloak, Cling Grip, and Clawline reduce the number of precise jumps and recoveries you need while cursed.
Faydown Cloak simplifies one near-top reach in the jail; without it, line up a safe pogo off the flying enemy.
Keep the Sinner’s Road bench functional if you’ve unlocked it; it reduces backtracking if you fall during the climb.
If Rosaries are tight, convert carryable valuables before you enter Sinner’s Road so you don’t risk a cursed return trip.

Act 3 caution and endings

Completing Infestation Operation cures Hornet. If you are pursuing the “cursed” ending path tied to staying afflicted during the Act 2 finale, do not complete this wish before that boss fight. Finish your ending requirement first, then return later to cure the curse.

Troubleshooting — merchants missing or “dead” in Act 3

Steel Spines don’t appear if Crull and Benjin are absent in Act 3 due to a known progression bug in early patches. The fix places the Steel Spines in their ruined home or restores the interaction.

Update to the latest patch. If a public beta channel is available on your platform, opt into it; the fix rolled out there first before reaching the live build.

Revisit Crull and Benjin’s room. After updating, check the same jail room and their residence; the Steel Spines will be obtainable without the original interaction if the vendors no longer appear.

If your platform doesn’t support the beta (e.g., some subscription storefronts), load an earlier autosave made before Act 3 where the vendors are present. On the save-select screen, use the small arrow to pick prior autosaves, then complete the wish, and continue.

For in-game guidance while cursed, speak to the bartender at Halfway Home in Greymoor; they can point you toward the doctor/cure path if you haven’t located Yarnaby yet.

FAQ — price and timing

Is the price fixed? Most players see a 260 Rosary price for Steel Spines, though earlier patches or certain states have shown lower costs. Bring 260+ to guarantee the purchase in one trip.

When should I do this? As soon as you can safely reach Yarnaby and Sinner’s Road. The curse suppresses healing and tools, so curing it promptly restores your full kit and grants the Witch Crest.

Once cured, healing and tools come back online, travel becomes safer, and the Witch Crest is added to your options—worth the brief detour even under curse restrictions.