Mana

Mana is the basic energy of the Universe, generated through unknown means by not only living things, but nonliving things like geological features or even meteorological activity. It is implied that Mana exists everywhere, but only actively influences the Universe to any great degree inside System Space. It powers the System and all System-powered beings and monsters.

Mana is everywhere, but accumulates faster in some areas than others. These are called "Medium Mana Areas" and "High Mana Areas." At System Start, Medium and High Mana Areas are much more dangerous than other places as the higher levels of Mana begin to change local animals and plants much faster than in ordinary areas.

The characters speculate that the reason System-powered beings and monsters are "tougher" than non-System powered counterparts is that Mana infuses their bodies, making them stronger and more durable.