The default Isabelle represents C.J., an anthropomorphic beaver who wears a vest.
The stage's background represents the player's island in Animal Crossing: New Horizons which first features C.J. as a special character.
Isabelle's favored Fishing Rod, as well as the stage and music track, references C.J.'s occupation as a fisherman who teaches the player to fish for aquatic life found in the seas and seashores.
The Inkling minions' frequent Super Jump, the Unira item, the Starfy Assist Trophy enemy, and the Goldeen Poké Ball Pokémon each represent the aquatic life in the Animal Crossing series, including squids, sea urchins, sea stars, and goldfish.
Other trivia:
This spirit's Support type and Item Gravitation ability reference C.J.'s role in New Horizons by allowing the player to purchase the fish they caught in New Horizons.
