[3][4] The designers of the set were Aaron Forsythe (lead designer), Mark Rosewater, Paul Sottosanti, Brady Dommermuth, Nate Heiss, and Andrew Finch; the developers of the set were Devin Low (lead developer), Bill Rose, Matt Place, Henry Stern, Mike Turian, and Doug Beyer.

[5] The plane is a pastoral world inhabited by several major races: boggarts (goblins), faeries, elves, giants, treefolk, merfolk, elementals (including the flamekin) and kithkin.

Five theme decks have been released as part of the set, one more than the standard four-per-expansion, which had been a long-time trend.

The preconstructed theme decks are:[6] "Kithkin Militia" (White), "Merrow Riverways" (White/Blue), "Boggarts' Feast" (Black/Red), "Elvish Predation" (Black/Green), and "Elementals' Path" (White/Blue/Black/Red/Green).

As revealed in an advertisement in the trade publication ICv2 and later confirmed by Mark Rosewater in his column, Morningtide expanded upon Lorwyn’s flavor and theme by focusing on at least five classes (Soldiers, Shamans, Wizards, Warriors, and Rogues) as well as a few minor class-based tribes (Druids, Archers, Knights, Clerics, and Assassins) in addition to the eight races of Lorwyn (Kithkin, Merfolk, Faeries, Elementals [Flamekin and Greater], Goblins, Giants, Treefolk, and Elves).

[9] The block has a tribal theme, now referred to in game as kindred, which focuses heavily on creature subtypes.

Hideaway, which appears on a cycle of rare lands, lets the player "hide" (exiling facedown) a card "away" for later.

Cards may be cast for their prowl cost if the player has dealt combat damage with a Rogue, often providing some additional effect.

Other races include the mermaid-like Merfolk, Ent-like beings called Treefolk, Faeries, Boggarts, Elementals, and Changelings.

While most of the groups live in relative harmony, the Elf race is cold and aloof, considering themselves superior and engaging in genocidal hunts against Boggarts and Elementals.

The protagonists include Rhys, a male elf who had received tutelage from a Treefolk sage and who was later exiled from his tribe; Ashling, a female fiery elemental who assists the heroes; the Vendilion Clique, triplet faeries siblings; and the mysterious Maralen, a female elf, who, despite attempting to control the chaos of the Aurora, doesn't appear who she seems to be.