My new take on the Gillmen for Hollow Earth Expedition moves them much more closely to the nereid/mermen/mermaid myths. One talent I decided to add was Siren Call, to more closely approximate the supposed seductive nature of the creatures.

Siren Call

Prerequisite: Charisma 3 or Performance 4

Your character has a preternaturally beautiful voice that can charm and enchant most creatures.

Benefit: Your character may attempt to attack a target using Performance (or Charisma, if untrained.) If you roll more than the Willpower of the target, that person or creature is entranced by your voice for the number of minutes equal to your successes. To continue to hold them in your sway, must must make another test. This cannot be used during combat, like Captivate, but the effect lasts much longer. While the character can manipulate, touch, or move their victim, they cannot injure or frighten them. This immediately breaks the spell.

Normal: Your character can sing with such beauty as to captivate a target for a short time. Advanced: This Talent can be bought up to three times, gaining a +2 to Performance for each level purchased. The effects last the level of the Talent in minutes x the successes over the target’s Willpower.