Level 1: Any weapon ability that deals rolled damage using this weapon gains a +1 damage bonus. Additionally, you can change the damage type of such abilities to cold, fire, lightning, or sonic.
Level 5: The weapon's damage bonus increases to +2. Additionally, the weapon can be used with ranged weapon abilities, and returns to you when a ranged ability is resolved. Ranged abilities used with the weapon increase their distance by 3, and must deal cold, fire, lightning, or sonic damage (chosen when you use the ability).
Level 9: The weapon's damage bonus increases to +3. Additionally, while you wield or carry the weapon, you have immunity 10 to cold, fire, lightning, and sonic damage.