Super Smash Bros. Ultimate

Super Smash Bros. Ultimate is a crossover Nintendo fighting game released on the Nintendo Switch in December 2018, directed by Masahiro Sakurai and developed by Bandai Namco Studios. Ultimate features a massive playable roster from the vast majority of Nintendo intellectual property such as Mario, Pokémon, and The Legend of Zelda, and several third-party companies also contribute characters and IP.

After the Super Smash Bros. installments released for the Wii U and 3DS notably removed Isaac's in-game cameo appearance from Super Smash Bros. Brawl and instead introduced a music track from Golden Sun: Dark Dawn, Ultimate brings back Isaac's role from Brawl with few changes and makes other minor references to the Golden Sun series. This makes Ultimate the first appearance of anything related to Golden Sun to visually appear in a new production since Dark Dawn was released near the end of 2010.

Golden Sun-related content
Super Smash Bros. Ultimate more-or-less keeps the Golden Sun IP at the same level of representation as it had in Super Smash Bros. Brawl.

Isaac as an Assist Trophy
Isaac returns as one of the dozens of computer-controlled "helper characters" that will be randomly chosen to appear if the player's own character grabs and uses the Assist Trophy item. He appears to exhibit similar behavior to his Brawl appearance, using the Move Psynergy and featuring the same lines of voice acting. Isaac, like all other Assist Trophies, can now be damaged and knocked aside like a standard playable character.

Matthew as a Spirit
Matthew from Golden Sun: Dark Dawn is represented in the game as one of the many available "Spirits" to fight and collect in the Spirits adventure mode. A Spirit, which is visually represented by a piece of static character art, represents an exclusive set of buffs and/or special effects that can be applied to any character it is assigned to. Matthew's Spirit is represented by his official character artwork accompanying Dark Dawn's promotional materials.

Battle music
"Battle Scene/ Final Boss (Golden Sun)", the progressive rock remix that medleys the default battle theme of Golden Sun: The Lost Age and the final boss theme from the same game, is slated to reappear.