The yellow Lucina represents Aisya, a sword-wielding princess who wears yellow armor.
The stage and music track represent the kingdom of Millenear, the main setting of ASH: Archaic Sealed Heat, a fantasy role-playing game released on the Nintendo DS.
The Shovel Knight Assist Trophy enemy's digging ability represents one of the fallen allies that Aisya raises from the ashes in Archaic Sealed Heat
The Bob-omb Festival rule references the beginning of Archaic Sealed Heat where Aisya witnesses her friends and family being destroyed by the Flame Serpent's attack on Millenear.
Other trivia:
This spirit's Shield type references Aisya's role in Archaic Sealed Heat to defend the kingdom of Millenear from the Flame Serpent.
In World of Light, the Aisya spirit is located in the Molten Fortress map in the Light Realm, which is occupied by fire-themed spirits, referencing the Flame Serpent, a fire-bodied flying serpent.
