Extra health for Hornet will go a long way when contending with the variety of bosses in Hollow Knight: Silksong. Increasing it requires assembling 4 Mask Shards to add a single point of health, and there are 20 of these Shards to be found, for a total of 5 additional health.
This guide for Hollow Knight: Silksong is a complete listing of all 20 Mask Shards and where to find them. There are multiple approaches to some Mask Shard locations, and the most recommended Ancestral Arts to have in hand are listed as pre-requisites.
Grotto
Buy for 300 Rosaries from Pebb at Bone Bottom.
Wormways
Pre-requisite: Swift Step
Enter via Grotto, and slip into the water. Obliterate the wall to the right.
Far Fields
Pre-requisite: Drifter’s Cloak
Ride the updraft to the right of the Seamstress, blasting your way through the rocks to the top.
Pre-requisite: Clawline, Drifter’s Cloak, Faydown Cloak
Bottom-right corner of Far Fields inside the skull cavern, triggers a gauntlet of enemy waves with some difficult platforming thrown in.
Pre-requisite: Clawline, Faydown Cloak, Silkspeed Anklets
Awarded from the third race versus Sprintmaster Swift.
Deep Docks
Pre-requisite: Cling Grip, Swift Step
Venture from The Marrow into the Deep Docks and defeat an enemy gauntlet at the start.
Bellhart
Defeat the Savage Beastfly in Far Fields, then return to the wish bulletin board.
Defeat Gurr the Outcast in the secret area beneath Far Fields, then return to the wish bulletin board.
Eliminate 12 Void Masses across Pharloom, then return to the wish bulletin board.
Shellwood
Pre-requisite: Cling Grip, Drifter’s Cloak, Swift Step
Furthest right within this area, you will have to platform over flowers and slice through some vines.
Weavenest Atla
Pre-requisite: Cling Grip, Drifter’s Cloak, Swift Step
Enter via Grotto, and face Widow. Through the gate, and get to the teleporter. Backtrack from there by heading upwards and then to the right. Platform over the hazards in order to reach the top left area.
Choral Chambers
Pre-requisite: The Wandering Merchant completion
Buy for 750 Rosaries from Jubilana at Songclave.
Beginning in Cogwork Core, descend and then head left straight into enemies. Once they are dispatched, open the door to the left.
Blasted Steps
Pre-requisite: Clawline, Faydown Cloak, Swift Step
From the Bone Bottom and Shellwood junction, head left, then upwards onto the platforms. Get past the enemies while continuing to platform.
The Slab Mask
Pre-requisite: Key of Apostate, Clawline, Cling Grip, Drifter’s Cloak, Faydown Cloak
From the leftmost bench in The Slab, head upwards right through the breakable ceiling. Open the lock with your previously acquired key, and make use of your abilities to complete the area.
Mount Fay
Pre-requisite: Faydown Cloak, Cling Grip
Go left from the leftmost bench and bust through the destructible wall. Continue left and into the hollow pillar, scaling it to the top.
Pre-requisite: Faydown Cloak, Clawline, Cling Grip, Silk Soar
From the middle, begin ascending to the very top of the section into the hidden room, then right. Bust through the obstruction, and then locate the entry through the ceiling. The enemies here will serve as stepping stones as you continue right using your various Ancestral Arts.
Whispering Vaults
Pre-requisite: Cling Grip, Drifter’s Cloak
Begin from the tall shaft section, ignore the lowest right path and aim for the next shaft above it. Continue right into the large room and upward to come around to the left exit passage. Within this smaller is a secret entry through the ceiling leading to the Mask Shard.
Bilewater
Pre-requisite: Clawline, Cling Grip, Drifter’s Cloak, Faydown Cloak
Beginning at the bottom of the largest shaft in Bilewater, head upward and into the passageway bearing right at the very top. Continue right, cutting straight across this smaller shaft and into another. Halfway up is the exit that leads further right. Proceed to the very end of this passage, then up and right.
Wisp Thicket
Pre-requisite: Clawline, Cling Grip, Drifter’s Cloak, Faydown Cloak
Begin from the tall shaft, and reach halfway up to find the passageway to the right. Evade the various fire attacks as you proceed to the very end of the area, and go up and left into the alcove.
Those are all 20 of the Mask Shards and their locations in Hollow Knight: Silksong.
