Despite the plain differences in appearance, Eve and Cassidy are the same kind of creature. High-density mana concentrations resulting in the local zeitgeist manifesting a living, breathing creature. However while Cassidy was incarnated from a single more or less cohesive idea and later adopted, Eve was... not so lucky.

The old mansion on the hill had been abandoned for decades, the menacing aura of gloom and its high fences keeping the town locals at bay, while its mysterious history led to story after theory after rumor after legend about who had lived there, what had happened to them... and what lurks there now.

Was it the ghost of the house's Lady? Was it a ravening monster? An amorphous creature of shadow and darkness? Nobody could agree, and as rumors came and went, Eve became many things over the years before managing to properly incarnate to flesh and blood and throw off the people's unwitting chains. Unchained though she is, the mix of thoughts have definitely left their mark as she's not entirely what she seems.