Rank 1: Increases the damage done by your Shadow Bolt spell by 2%, and your Shadow Bolt has a 20% chance to cause your target to be vulnerable to spell damage, increasing spell critical strike chance against that target by 5%. Effect lasts 30 sec.

Rank 2: Increases the damage done by your Shadow Bolt spell by 4%, and your Shadow Bolt has a 40% chance to cause your target to be vulnerable to spell damage, increasing spell critical strike chance against that target by 5%. Effect lasts 30 sec.

Rank 3: Increases the damage done by your Shadow Bolt spell by 6%, and your Shadow Bolt has a 60% chance to cause your target to be vulnerable to spell damage, increasing spell critical strike chance against that target by 5%. Effect lasts 30 sec.

Rank 4: Increases the damage done by your Shadow Bolt spell by 8%, and your Shadow Bolt has a 80% chance to cause your target to be vulnerable to spell damage, increasing spell critical strike chance against that target by 5%. Effect lasts 30 sec.

Rank 5: Increases the damage done by your Shadow Bolt spell by 10%, and your Shadow Bolt has a 100% chance to cause your target to be vulnerable to spell damage, increasing spell critical strike chance against that target by 5%. Effect lasts 30 sec.