The Bond of Contracts

This story is that I made from my dream which I saw after watching Darker Than Black.Its about a girl who belongs to a family of powerful magic wielders whose abilities can only be awakened when they form a contract with someone, it doesn't matter whether it's a boy or a girl though it is preferred that you form it with a person of high potential.But there is a rule of not forming one with a person who is in danger of dieing because then the contract is shared not given completely, meaning if the contract was ever broken the person who forms it will die along with the dead person.