Nerissa is the mother of Zac Blakely and Mimmi. She left to join the Eastern pod in the battle against the rebel mermaid Aurora, so she left her daughter Mimmi and her son Zac when they were very young, She was turned into a fearsome water dragon by Aurora and attacked Weilan's pod under Aurora´s control. After the attack on the Eastern pod she fell into a deep slumber until she felt Zac and Mimmi had found each other. She felt the connection between Mimmi and Zac growing stronger and as a result, the spell that transformed her into the dragon began to lift. Finally, she woke up and saw Weilan in the Chinese waters and followed her to Mako when Weilan swam away, scared. She is also a descendant of the merman who created the merman cave. And she is also known for being a very powerful mermaid.