Planeswalkers

Planeswalker is also the name of the second book of the Artifacts Cycle.

Planeswalkers are among the most powerful beings in the multiverse, and are the thematic identities of the players of the game. Planeswalkers can be born at random in any sentient race, with no outward signs of their latent power. However, there is the incredibly remote chance that any given sentient, natural being is born with a planeswalker's spark. When that being is put through a period of extreme stress -- in many cases, death -- the spark can trigger, causing the individual to ascend and become a planeswalker. In certain extremely rare cases, it is possible to transfer a spark from one being to another, but no one is sure of the precise means, it is highly risky, and nearly impossible to convince a planeswalker to give up their power.

Planeswalkers have incredible magical capabilities, surpassing all but the most powerful mortal wizards. Planeswalkers' lives can last indefinitely, and their physical forms are matters of will. Finally, planeswalkers can travel between separate universes with ease, while the vast majority of people throughout the multiverse are not even aware that other universes exist. Because of planeswalkers' prolonged lifespans and immense power -- some are worshipped as gods -- many end up somewhat insane, or at the very least, come to regard the lives of mortals in low esteem if they regard them at all.

A planeswalker is specifically a being who possesses a planeswalker's spark. There are other beings who, through various means, are able to travel between planes, but those are not technically considered planeswalkers. Many prerevisionist characters were referred to as planeswalkers but may not technically have been; without any further information, they shall remain subject to debate.

Also see: List of planeswalkers