Fire Emblem if, which features two warring factions, is going to be available in two boxed retail versions (above), each one playing through the game from one side’s perspective, with a different story and unique characters. If you buy one of these boxed versions and want to see how the other goes down, though, you can buy the other campaign as DLC at a discounted rate.
(Oh, and there’s a third campaign, included in neither boxed edition, that’s available only as DLC.)
There’ll also be a special edition made available, which bundles the light, dark and third campaign in a single purchase, along with other stuff like an art book (below).