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From Pathfinder Rage of Elements, which isn't enabled.

Thorn Triad (Major)

ITEM 12
MAGICALSPELLHEARTWOOD
Price 1800 gp
Usage affixed to non metal armor or a weapon
Bulk L

From each corner of this carved, triangular badge extends a long, sharp thorn. The spell DC of any spell cast by activating this item is 29.

  • Armor After you cast a plant spell by activating the triad, you gain resistance 6 to bludgeoning and piercing damage and weakness 3 to fire until the end of your next turn, or double the resistance for a non-cantrip spell.
  • Weapon After you cast a plant spell by activating the triad, thorns erupt from the weapon. Your Strikes with the weapon deal an additional 1d8 persistent bleed damage until the end of your next turn.

Effect: Thorn Triad - Armor

Effect: Thorn Triad - Weapon

Activate Cast a Spell
Effect You cast Timber.
Activate Cast a Spell
Frequency once per day
Effect You cast 4th-rank Wall of Thorns.
Activate Cast a Spell
Frequency once per day
Effect You cast Petal Storm.
Pathfinder Rage of ElementsOGL