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Keen Edge

School transmutation; Level bloodrager 3, inquisitor 3, magus 3, sorcerer/wizard 3; Subdomain murder 3; Elemental School metal 3

CASTING

Casting Time 1 standard action
Components V, S

EFFECT

Range close (25 ft. + 5 ft./2 levels)
Targets one weapon or 50 projectiles, all of which must be together at the time of casting
Duration 10 min./level
Saving Throw Will negates (harmless, object); Spell Resistance yes (harmless, object)

By the way...
This spell also affects siege engines and siege engine ammunition.

Source Skull & Shackles Player's Guide