In Super Smash Bros. Ultimate, the title of the game's main theme song is “Lifelight.”
The song was composed by Hideki Sakamoto, with vocals performed by singer-songwriter Shōko Nakagawa. It serves as the central original theme for Ultimate and is closely associated with the game's opening movie and its World of Light adventure campaign.
“Lifelight” is easy to confuse with the many famous rearranged tracks in Ultimate. The game contains music from across Nintendo history and numerous third-party series, including songs such as “Gourmet Race” and “One-Winged Angel.” Those are stage or series music selections, not the game's main theme.
Ultimate's soundtrack was unusually large: Nintendo advertised more than 800 songs at launch, while the complete game and downloadable content expanded the total further. The main theme's melody also appears in arrangements used throughout the game's original music.