Keen Edge

Transmutation

Level: Mage 3; Components: V, S; Casting Time; Attack action Range: Close (25 ft. + 5 ft./2 levels); Targets: One weapon or 50 projectiles, all of which must be in contact with each other at the time of casting; Duration: 10 minutes/level; Saving Throw: Will negates (harmless, object); Spell Resistance: Yes (harmless, object)

This transmutation doubles the threat range of the weapon. A threat range of 20 becomes 19–20. A threat range of 19–20 becomes 17–20. A threat range of 18–20 becomes 15–20. The spell can be cast only on piercing or slashing weapons (and it does not stack with itself). If cast on arrows or crossbow bolts, the keen edge on a particular projectile ends after one use, whether or not the missile strikes its intended target.

This spell cannot be cast on a natural weapon, such as an unarmed strike.