This game is like Lioden or Flightrising except it is more of a choose your own adventure. You start of with a demon you find by adventuring out and meeting it. Forever that demon is your soul demon, they will never retire. To change your soul demon you must tell your demon that they have worked hard and chant this spell, 'Daemonium, et servivit tibi ad tua vacat vobis, liberum'.  The spell sends the demon to retirement. Demons can not die of old age but die of other causes such as starvation, mutations, neglect, unsafe food, being killed while on an adventure. Demons won't die on an adventure, when they are low health they will flee. If you force a demon to keep fighting that is when it will die.