Seiren was a Cardian released by Ail and An with the mission of gathering energy from humans in order to revive the Makaiju. She resembled a pink haired mermaid, and could use her long hair to incapacitate her enemies and drain them of their energy; she absorbed the energy into her hair, which made it turn blue. Her main target was Rei. She attacked by firing a stream of water at her target. This attack managed to neutralize Sailor Mars' Fire Soul, but proved useless against Fire Soul Bird.
Trivia
- Seiren's name is a direct reference to the siren of Greek mythology.
