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From Pathfinder Lost Omens Rival Academies, which isn't enabled.

Snakebird's Shadow

FEAT 8
Activity 2 actions
Prerequisites Waterfowl Stance

Requirements You are in Waterfowl Stance and are wielding a monk weapon from the sword group.

Ganhil developed this technique through observing the sharp-beaked darters fishing Prada Hanam's waters, seeking to match their speed and suppleness with the elemental flash of his blade. Make a melee Strike with the required weapon against each enemy in a 15-foot line as razor-sharp shadows of water surge from your blade. Each attack counts toward your multiple attack penalty, but you do not increase your penalty until you have made all your attacks.

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