Magical Weapon: Bloodthirst Bow

[Northern Guard]

Here's a magical weapon I cooked up for one of the player character's in my game:

Vance's Bloodthirst Bow, Level 2+
This bow seeks a quick end to its wielder's foes. The fletching and shaft of an arrow fired from the Bloodthirst bow are stained a dark crimson hue. At dawn, the limbs of this bow are bone white but will quickly turn a bloody red as the wielder hunts and strikes down his or her quarry.

Lvl 2 +1 520 gp

Enhancement: Attack rolls and damage
Critical: +1d6 damage per plus, +1d12 per plus if the target is bloodied
Power (Daily): Free Action. Use this power when you hit a bloodied target with this weapon. Make a basic attack with this weapon against the same target.

As always, comments and constructive feedback are welcome.