A Horcrux is an object in which someone has concealed part of their soul. By splitting their soul and hiding it outside of their body, they would not be able to die even if their body was destroyed. However, creating a Horcrux involves committing an act of supreme evil – murder. Killing someone rips the soul apart, allowing the witch or wizard to use magic to encase a fragment of it. Creating one Horcrux is monstrous enough but Voldemort wished to create seven.