Beloved is a shounen-ai fantasy novel set in a world where half the soul of a person is in their own body, while the
other half resides inside the body of an eyeless companion known as a Beloved. In this world, Kadono Naiyuki is the only known
person without one.
The Concept of Beloved
Basically, normal people are known as Models, while the person who has the other half of their soul are known as Beloved.
Beloved have no eyes, and can only see while holding the hand of their Model. They also lack last names.
Since you can't survive with only half a soul, if a Beloved or Model dies, the other dies too. Generally a Model's
Beloved will appear to them during their first few days of life. Naiyuki is 17, and has basically determined that he doesn't
have Beloved at all, seeing as how it's almost unheard of for one's Beloved to take a week to show up, let alone
17 years.