This is a combat system for those with magic deck of cards. It allows PCs to utilize their card playing skills to resolve RPG combat.
If your character has access to such a deck, you will use these rules.
As population increases, animal souls are promoted to human before they are spiritually advanced enough in terms of impulse control, etc.: this shouldn't have happened, but karmic progression is automatic, after all--it's a force of nature. But the 'animalization' of humankind bodes ill for civilization.
No doubt the same goes for elves, dwarves, and so on.