The Blightslayer Reliquaries

When The Blightslayers killed a demigod during the war between man and divinity, they captured his soul and split it among 6 containers so that it could be secured. If he were ever raised, they feared his wrath, and thought the best way to protect against it was to guard these reliquaries. Each one is made from a different material, and each opens with a key. Copies of the key were given to trusted individuals, but after the Blightslayers died out, the keys were spread and the reliquaries searched out.