Here is an overview of the demo and game, via Nintendo:
In the demo, you take on the role of a lone mercenary on a quest for answers after suffering a brutal defeat at the hands of the mysterious Ashen Demon. Join Edelgard, Dimitri, Claude and other Fire Emblem: Three Houses characters and lead your companions in real-time battles that blend the strategy of the Fire Emblem series with action-packed Warriors-style gameplay.
Take command of the battlefield and use tactical know-how to gain the upper hand. Employ flashy combos and powerful special abilities against hordes of enemies from the beginning of the game through the first three chapters! The demo will also support local two-player co-op play so you can flex your arms alongside a friend. Plus, you can carry your progress over to the full game when it launches.
In Fire Emblem Warriors: Three Hopes, the protagonist quickly finds themself wrapped up in a growing conflict that will determine the future of Fódlan. Align with one of the three leaders and build an army as you fight in multiple large-scale battles. The house you choose will bring you through one of three dramatic stories, each with a different outcome. If you purchase the full game, you’ll be able to further forge relationships between characters, experience epic combat and unravel each diverging path and engaging storyline as you fight to shape Fodlan’s destiny.
Fire Emblem Warriors: Three Hopes is due out for Switch on June 24.
Watch the trailer below.