Content with her ordinary life, Lyra is somewhat of a wallflower. However, her comfortable lifestyle suddenly goes astray when she accidentally plunges into the world of sirens. Entangled in a curse, Lyra will learn that her world may be a lot bigger than she had ever imagined.
The main protagonist, she was adopted by her grandmother at a young age after being found abandoned on the beach. She has a crush on Shon but, after he cancels their plans so he could hang out with his girlfriend, she is heartbroken; being cursed to be a half-human, half-siren, after falling into the ocean and getting kissed by Ian. As a siren, she appears to have a yellow heart, unique to sirens.
A siren who passes half of his curse onto Lyra, while trying to become human. He is now a half-human, half-siren. He doesn't remember anything about himself, only knowing the cold loneliness of being a siren. Through the story, he develops a close relationship with Lyra and is seen to have a crush on her.
Lyra's first and main love interest, he has been friends with her since their childhood. In episode 84, he takes on Lyra's curse to save her, turning himself into a siren. As a siren, he can not remember his past or relationship he had shared with Lyra. He appears to have a unique green heart to sirens. Before turning siren, he was a sweet, very kind soul who always put others before himself and helped Lyra through times of trouble.
A siren who is good at telling stories. He wants friendship and grows close to Pele, despite being a siren. He is later caught by Siren Hunters but convinces one to transfer the curse onto himself, making Tua human. He is a charismatic young man and a very lovable, talkative character.
A siren who is said to be good at dancing, she prophesied, by Crim, to bring about despair. She is chosen by Poseidon, turning her back into a human.
A blind siren who has visions of the future. He wielded a golden medallion that Lyra stole from him. He is portrayed to be a creepy character. He is later killed and turned to sea foam by Aleah.
Lyra's adopted grandmother who is in the hospital. She used to own their flower shop, Carnations. She dies after giving Lyra the remainder of her power.
Shon's little sister and “Lyly’s” best friend. A sweetheart and cutie, she stops at nothing to support her friend and family.
Shon's ex-girlfriend. Beautiful yet cunning, she is one of the most interesting characters because of her mysterious background and relationship with Lyra and all sirens. She is known as “the Poseidon” and "an oversized Barbie doll" from Kori. She is revealed to be Hona's (Granny's) sister, Ophelia, and created the curse after her lover, Calder, died at sea.
Aleah, the Poseidon, seems to control sirens, their minds, and even their memories.