Regine is Herve and Suzette's mother. She wrote a letter to Ellen to lure her to Doolin in order to enact a 17 year old revenge plot. When Ellen finds her, Regine is already murdered and her body falls of the cliff.
Ever since the deaths of both her husband Renaldo, and her son Herve, Regine had been border-lining insane. Her daughter, Suzette, had never gotten to meet either of them, so she especially saw the bad side of her mother. Regine often saw her daughter as her dead son and wouldn't let her out of the house, but on other days she saw that her daughter wasn't him and beat her.
Part of the reason for her irrational behavior was the seventeen-year-old grudge that she'd held against Cecilia for "murdering" Herve. (Thanks to Dr. Lester's silence and Ryan's photo, everyone in the village supported Regine's theory of murder.)
When at last Regine found Cecilia's (AKA Ellen's) whereabouts, she called her back to the village to murder her, like the young girl murdered Herve.
However, before Regine could put her murder-plot into action, Ellen's mother overheard her scheme and mudered her, before she could murder Ellen. (See more from Ellen's mother to get the whole backstory of this.)
In the Netherworld, Keats gets to speak with Regine and she tells him to warn her daughter, who she is surprisingly very worried about, to leave the village or she will be murdered as well.
- Régine is a variant of Regina (Latin), and it means "queen".