Shadowmoor was linked thematically to Lorwyn, and the four sets comprising the two blocks rotated through official tournament formats together.

The designers of the set are Mark Rosewater (lead), Sean Fletcher, Mark Gottlieb, Devin Low, and Ken Troop; the developers of the set are Aaron Forsythe (lead), Devin Low, Alexis Janson (the winner of The Great Designer Search Contest[4]), Matt Place, Jake Theis, Steve Warner, and Doug Beyer.

"[5][6] Rosewater also stated that "the set plays into the duality theme between Lorwyn and Shadowmoor blocks, both in the art and the mechanics.

[17] Eventide continues the block theme of hybrid cards and color matters that Shadowmoor started, as well as further use of the Wither and Persist key words.

During one particular manifestation of the Great Aurora (a recurring tri-centennial event that transform the peaceful inhabitants of Lorwyn into negative versions of themselves, in which they cannot remember their former selves), the Faerie race appear to be unaffected.

In the story of the previous block Time Spiral, there was a much worse cataclysmic event known as the Mending, which had caused rifts in time-space as well as a significant reduction of magic power used by Planeswalkers.

The time discontinuity also influences the Lorwyn plane, causing the Aurora to manifest much earlier than expected, out the control of Oona.