Sheila

A young mermaid princess that was fiercely attacked by Seine in the past, she somehow escaped but was pretty much dead. In the end she somehow survived by merging with a drowned girl's corpse (a taboo for mermaids), but couldn't heal completely. As a result, she lost her voice and her body starts to rot painfully if she's on dry land for too long. Though she came to the surface for revenge, she has a gentle nature and apparently is easily influenced by others.