Requirement: Perform 15 ranks
Base effect: All enemies within 30 feet gain 5 point of bleed damage at the beginning of your round. This damage stacks with itself, up to a total of 25 points of damage, but not with other sources of bleed damage. Removing this bleed damage is harder than normal, as it can only be removed by healing magic if the caster succeeds at a caster level check (DC = 10 + siren level).
You channel negative energy in a beam of death. To use this refrain, make a ranged touch attack against one enemy within 30 feet and, if successful, the target suffers negative energy damage. A successful Fortitude saving throw halves the damage. If this attack is a critical hit and the target fails its save, it is instantly slain regardless of the damage inflicted.
Weak Refrain: the target suffers 1d4 points of damage per siren level (max 10d4).
Intermediate Refrain: the target suffers 1d6 points of damage per siren level (max 15d6).
Strong refrain: the target suffers 1d8 points of damage per siren level (max 20d8).