Eve lived in a cave in the Dreaming, and was often accompanied by Dream's raven, Matthew. The first Raven, Lucien, taught her how to bury Abel after Cain murdered him, and she had been accompanied by a Raven ever since.
She is often kind, and has a maternal nature, though she retains her assertiveness that might have been seen more as snappishness. Most of the time she appears as a black-haired woman of indeterminate age. However, her appearance also mirrors her triple nature; she sometimes shifts between being a young attractive maiden, a middle aged mother, and an elderly crone. She is one of the many representations in The Sandman of the triple woman (maiden, mother, and crone), as such, while she is an individual, with her own personality, she is also a representation of The Three, along with the Fates, Graces, Gorgons, and Furies. This is comparable to the way the series' protagonist, Dream, is on one level a character in his own right, and equally a symbol or representation of the larger concept of dreams.
She recovers over the course of the series, In issue #24, she has put on weight, has a friendlier face, and shows her ability to become younger as she embraces Matthew. When she appeared in #40, she appeared young and beautiful for the first time.
Eve is based on the Biblical Eve, the mother of humanity, and of Cain and Abel, and consort of Adam.