Who is The Beloved from The Four Loves and what is their importance?

A Beloved is a person who is loved by another. Note, that love, as explained by Lewis, is not simply friendship or affection, but rather Eros, the deep and abiding love that transcends all personal goals, needs, or sexual desire. That doesn't mean, however, that those things don't play a role. What it means is that they take a back seat to the Beloved's needs.