Souls

Souls are usually cycled between worlds for reincarnation.

The System forces souls into a closed cycle. Each time a soul reincarnates within the System, it is damaged slightly. Over the long history of the System, the souls of its natives have become steadily more and more damaged, to the point that some souls have already collapsed: the System was not built to operate for as long as it has.

The reincarnators are each marked with an skill so that they will be automatically returned to the normal cycle when they die.