Bone Flute

Bone Flute

CommonNecrobinder
Whenever Osty attacks, gain 2 Block.

Every time Osty attacks on your behalf you gain 2 Block. The relic checks that the attacker is your own Osty, so a partner's Osty does not count. The Block is Unpowered, so Dexterity does not change it. Each attack command is one trigger; a card that makes Osty hit several times in one command still gives 2. It unlocks at Futility.

Rarity
Common
Character
Necrobinder
Shop price
175 gold
Unlock
FutilityBeat Act 2 with the Necrobinder

When to take Bone Flute

Take it early in an Osty-attack deck, Poke, Fetch and Unleash can give three or four attacks a turn for 6 to 8 free Block. Weak in a Doom or Soul deck.

Cards that synergize with Bone Flute

Fetch
Attack
0
Osty deals 3 damage.
If this is the first time this card has been played this turn, draw 1 card.
Fetch and Poke are 0-cost triggers.Osty deals 3 damage.
If this is the first time this card has been played this turn, draw 1 card.
Poke
Attack
0
Osty deals 6 damage.
Fetch and Poke are 0-cost triggers.Osty deals 6 damage.
Right Hand Hand
Attack
0
Osty deals 4 damage.
Whenever you play a card that costs or more, return this to your Hand from the Discard Pile.
Right Hand Hand keeps coming back.Osty deals 4 damage.
Whenever you play a card that costs or more, return this to your Hand from the Discard Pile.
Sentry Mode
Power
2
At the start of your turn, add 1 Sweeping Gaze into your Hand.
Sentry Mode adds a free Sweeping Gaze attack each turn.At the start of your turn, add 1 Sweeping Gaze into your Hand.
Flatten
Attack
2
Osty deals 12 damage.
This card costs 0 if Osty has attacked this turn.
Flatten becomes free after the first attack.Osty deals 12 damage.
This card costs 0 if Osty has attacked this turn.
Calcify
Power
1
Osty's attacks deal 4 additional damage.
Calcify makes each of those attacks hurt.Osty's attacks deal 4 additional damage.
Reanimate
Skill
3
Summon 20.
Exhaust.
Reanimate Summons Osty, whom Bone Flute counts onSummon 20.
Exhaust.
Afterlife
Skill
1
Summon 6.
Exhaust.
Afterlife Summons Osty, whom Bone Flute counts onSummon 6.
Exhaust.
Bodyguard
Skill
1
Summon 5.
Bodyguard Summons Osty, whom Bone Flute counts onSummon 5.
Legion of Bone
Skill
2
ALL players Summon 6.
Exhaust.
Legion of Bone Summons Osty, whom Bone Flute counts onALL players Summon 6.
Exhaust.
Necro Mastery
Power
2
Summon 5.
Whenever Osty loses HP,
ALL enemies lose that much HP as well.
Necro Mastery Summons Osty, whom Bone Flute counts onSummon 5.
Whenever Osty loses HP,
ALL enemies lose that much HP as well.
Pull Aggro
Skill
2
Summon 4.
Gain 7 Block.
Pull Aggro Summons Osty, whom Bone Flute counts onSummon 4.
Gain 7 Block.
Cleanse
Skill
1
Summon 3.
Exhaust 1 card from your Draw Pile.
Cleanse Summons Osty, whom Bone Flute counts onSummon 3.
Exhaust 1 card from your Draw Pile.
Dirge
Skill
X
Summon 3 X times.
Add X Souls into your Draw Pile.
Exhaust.
Dirge Summons Osty, whom Bone Flute counts onSummon 3 X times.
Add X Souls into your Draw Pile.
Exhaust.
Sic 'Em
Attack
1
Osty deals 5 damage.
Whenever Osty hits this enemy this turn, Summon 3.
Sic 'Em Summons Osty, whom Bone Flute counts onOsty deals 5 damage.
Whenever Osty hits this enemy this turn, Summon 3.
Spur
Skill
1
Retain.
Summon 3.
Osty heals 5 HP.
Spur Summons Osty, whom Bone Flute counts onRetain.
Summon 3.
Osty heals 5 HP.
Invoke
Skill
1
Next turn, Summon 2 and gain .
Invoke Summons Osty, whom Bone Flute counts onNext turn, Summon 2 and gain .
Devour Life
Power
1
Whenever you play a Soul, Summon 1.
Devour Life Summons Osty, whom Bone Flute counts onWhenever you play a Soul, Summon 1.
Beacon of Hope
Power
1
Whenever you gain Block on your turn, other players gain half that much Block.
Beacon of Hope makes Block count for more, and Bone Flute gains itWhenever you gain Block on your turn, other players gain half that much Block.
Entrench
Skill
2
Double your Block.
Entrench makes Block count for more, and Bone Flute gains itDouble your Block.
Prolong
Skill
0
Next turn, gain Block equal to your current Block.
Exhaust.
Prolong makes Block count for more, and Bone Flute gains itNext turn, gain Block equal to your current Block.
Exhaust.

Relics that synergize with Bone Flute

Phylactery Unbound
Phylactery Unbound Summons Osty, whom Bone Flute counts onAt the start of each combat, Summon 5. At the start of your turn, Summon 2.
Bound Phylactery
Bound Phylactery Summons Osty, whom Bone Flute counts onAt the start of your turn, Summon 1.
Parrying Shield
Parrying Shield makes Block count for more, and Bone Flute gains itIf you end a turn with at least 10 Block, deal 6 damage to a random enemy.
Sturdy Clamp
Sturdy Clamp makes Block count for more, and Bone Flute gains itUp to 10 Block persists across turns.
Pael's Legion
Pael's Legion makes Block count for more, and Bone Flute gains itDoubles Block gained from a card, then goes to sleep for 2 turns.
Vambrace
Vambrace makes Block count for more, and Bone Flute gains itThe first time you gain Block from a card each combat, double the amount gained.
✦

Related relics

Big HatBook Repair KnifeBookmarkBound PhylacteryFunerary MaskIvory TilePhylactery UnboundUndying Sigil

Changes by version

  1. 19 Feb 2026ArtInternal playtest
    Added assets
    TextInternal playtest
    Enormous Ring to Bone Flute

Internal playtest notes are from before the Early Access release. Names and numbers in them can differ from the game today.

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