OathbowWeapon 11
Source Pathfinder Core Rulebook
Damage 1d8 Piercing
Type Martial
Range 100 feet
Price 1,300 gp
Weight 2 bulk
Constructed of a flexible, white wood and with ornate, twisting designs carved into its surface, this +2 striking composite longbow appears to have been made by elves. Sometimes when you loose an arrow, its whistling in flight sounds like a voice whispering in Elven, wishing for the swift defeat of your enemies.
Activate 
command
Effect You swear an oath to destroy one creature you can see. For the next 7 days or until that creature is slain, your attacks with the bow against that creature deal 1d6 additional damage, and you gain a +2 circumstance bonus to Survival checks to Track that creature.
Your critical hits against the target gain the bow's critical specialization effect; if they would already do so, they instead increase the DC of the Athletics check to Escape when critically hit to DC 20.
After you activate the bow, you can't activate it again for 7 days. If you kill the creature you've sworn an oath against, the oath ends and you need to wait only 10 minutes before you can activate it again.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
DeadlyOn a critical hit, the weapon adds a weapon damage die of the listed size. Roll this after doubling the weapon's damage. This increases to two dice if the weapon has a greater striking rune and three dice if the weapon has a major striking rune. For instance, a rapier with a greater striking rune deals 2d8 extra piercing damage on a critical hit. An ability that changes the size of the weapon's normal damage dice doesn't change the size of its deadly die.
DivinationThe divination school of magic typically involves obtaining or transferring information, or predicting events.
MagicalSomething with the magical trait is imbued with magical energies not tied to a specific tradition of magic. A magical item radiates a magic aura infused with its dominant school of magic. Some items or effects are closely tied to a particular tradition of magic. In these cases, the item has the arcane, divine, occult, or primal trait instead of the magical trait. Any of these traits indicate that the item is magical.
PropulsiveYou add half your Strength modifier (if positive) to damage rolls with a propulsive ranged weapon. If you have a negative Strength modifier, you add your full Strength modifier instead.
VolleyThis ranged weapon is less effective at close distances. Your attacks against targets that are at a distance within the range listed take a -2 penalty.