Requirement: Perform 3 ranks
Base effect: Allies within 30 feet gain a +5-foot enhancement bonus to each of their movement speeds and a +1 dodge bonus to AC and Reflex saves. The bonus to movement becomes +5 feet higher at 5th and 15th level (maximum +15 feet at 15th level). The dodge bonus becomes 1 point higher at 10th and 20th level (maximum +3 at 20th level).
You summon an arc of lightning in a 30-foot long line starting from your position. The creatures in this area suffer electricity damage, which is halved on a successful Reflex save.
Weak Refrain: Creatures in the area suffer 1d4 points of damage per siren level (max 4d4).
Intermediate Refrain: Creatures in the area suffer 1d6 points of damage per siren level (max 8d6).
Strong refrain: Creatures in the area suffer 1d8 points of damage per siren level (max 12d8).