World of Light

World of Light is the Adventure mode in Super Smash Bros. Ultimate. Unlike The Subspace Emissary, which is very plot-heavy, World of Light is used to demonstrate the functionalities of spirits and spirit battles, and has a very loose plot to leave the player free to explore the light and dark realms of the Adventure mode. World of Light also has considerably fewer cutscenes than The Subspace Emissary, though most of them are silent, akin to The Subspace Emissary's cutscenes; the lone exception being the introductory scene. The World of Light has a board game-like map, and elements and maps based on various games have been shown; Warp Pipes and ! Switches are noticeable.

During the events of the Adventure mode, a monster called Galeem defeats all of the fighters except Kirby, imprisoning them in the eponymous World of Light, where they are cloned and their clones are possessed by spirits, which are the other victims of Galeem's attack. Once Kirby has freed Mario and more fighters and spirits in the Light Realm and defeated Galeem, a new monster named Dharkon appears, opening a path to the Dark Realm, forcing Galeem to retreat. When the remaining fighters and spirits are freed in the Dark Realm (as well as defeating Dharkon), Galeem appears to confront Dharkon, putting the player in a third realm: a mixture of the Light and Dark Realms.

Within the mode, only Kirby is available from start; the rest of the fighters are unlocked though the mode's progress in matches similar to those of Challenger's Approach (the exception being Bowser, who becomes playable after defeating Giga Bowser). Downloadable characters can be made available to play as in World of Light by freeing 10 fighters in the mode. If the character in question is downloaded with the criteria having been met beforehand, then the character is immediately unlocked.

Three endings exist in World of Light: two bad endings with Galeem or Dharkon respectively, and a true ending with both bosses. The first ending is achieved by defeating too many dark puppet fighters, thus forcing the player to fight Galeem; when Galeem is defeated, Dharkon destroys Galeem and his army, encroaching the universe in darkness. The second ending is achieved by defeating too many light puppet fighters, thus forcing the player to fight Dharkon; when Dharkon is defeated, Galeem unleashes another wave of light, essentially engulfing the universe in light again. The third ending is achieved by defeating an equal number of light and dark puppet fighters, making the player fight both Galeem and Dharkon simultaneously; when the player wins, the universe is restored to its original state, while all spirits fly back to their original worlds.