The Magic multiverse contains an infinite number of planes, each containing countless civilizations and races. In between these planes are the Blind Enternities which rip any traveler apart into nothing if they are not one of the lucky few that have a Spark, an innate magical power that allows a being to walk between planes. A Planeswalker.
Magic's history is split into two defined eras: Pre-Mending and Post-Mending. Pre-Mending saw the Planeswalkers as virtual gods that played with the fates of the entire multiverse. However, this meddling resulted in the time stream being fractured, which required numerous Planeswalkers to give up their Sparks to heal these rifts. This led to the Post-Mending era, which saw the dramatic reduction in a Planeswalker's inherent power and is the current era of Magic.