Shards of Alara

"Five worlds share one fate": Alara was a single plane once, a massive world rich with mana. However, those same resources led to its downfall, for an unknown planeswalker tore the plane asunder millennia ago, harvesting of its mana. This disaster broke Alara along color lines into incomplete planes called shards, as light is diffracted by a prism. The shards recovered their mana in time, but only in part. Each shard is vastly different, as the combinations of triple-colored mana have shaped natural and cultural forces on each world in distinctive ways.