The Legend of Elkai

In the Highlands of Tarkir, the changing of the seasons are treated with much reverence. It is believed that a fey creature known as Elkai is responsible for their change, but no one has been able to prove this creature's existence. Most myths describe the being as an elk, or perhaps a unicorn, covered in things like moss, leaves, branches, and frost. It changes throughout the season, and its antler(s) take on the guise of a tree.
Legends about how the seasons change is varied as well. The most common legend states that Elkai runs through the Highland forests at the cusp of every equinox and solstice, hibernating and hiding from others the rest of the year. As it runs, it "pollinates" the land with the next season. If Elkai's run was prevented, the seasons may be forever stuck, disrupting the cycles of life and causing an immense downfall.
Some Tarkirians have taken to this legend as of late as a source of comfort. After the war with the Machavians and their encounter with Syka the Eternal Winter, many fear what would happen if the season weren't able to change. Faith in Elkai provides faith that balance will always be maintained, no matter how brutal the chill of winter becomes.