Byleth's blue costume is based on Dimitri, the leader of the Blue Lions house whose post-timeskip weapon Areadbhar serves as Byleth's side special.
The white Ganondorf minion represents Dedue, the muscular retainer of Dimitri who wears a black-and-white outfit.
The stage represents Tailtean Plains in the seventeenth Crimson Flower chapter of Fire Emblem: Three Houses, which features the final boss battle against Dimitri.
The music track is based on the theme song of the seventeenth Azure Moon chapter of Three Houses, which features Dimitri as a party member.
