I wonder how that would work myself, moreso for Xenoblade's inclusion than Fire Emblem. Fire Emblem has oodles of history, characters, and lore that could be utilized in various ways, so it wouldn't be too far out of the question for an action-based Fire Emblem game to be developed at some point. Xenoblade on the other hand is very much self-contained, and I can't figure how Shulk and the gang could bring anything to a Fire Emblem title. Any ideas?