The Subspace Emissary

The Subspace Emissary is the Adventure mode in Super Smash Bros. Brawl. It tells the story of the Subspace Army, led by the Ancient Minister, and its attempt to bring the world into Subspace. The story includes every playable character featured in the game except Toon Link, Jigglypuff, and Wolf who can be found on certain levels after beating the story, and intertwines the characters worlds so that they meet and interact. Most levels appear to require the player to choose between one of a few characters that are available. There is also a Co-op mode that allows two players to play at the same time. Most of the enemies in the Subspace Army make their debut in Brawl, while most of the bosses have appeared in previous Nintendo titles.

Link's Role
Link appears in a forest where he finds the Master Sword and teams up with Yoshi upon being attacked by the Subspace Army. Depending on which princess was saved, Link will either confront a mind-controlled Peach or confront Mario and Pit after seeing Zelda supposedly dying. They later team up and track down King Dedede.

Zelda's Role
Zelda watches as Mario and Kirby fight in the coliseum along with Peach who seems to be a good friend of hers. Zelda can either be saved or captured by Wario in the beginning. If she is saved, she will journey with Kirby only to later be captured by Bowser after Kirby leaves her behind. If she is captured by Wario, Shadow Bugs will create a replicate of her, which Mario and Pit have to defeat. She, along with Peach, is later saved by Solid Snake and transforms into Sheik. She then confronts Fox in his Arwing, forcing him to abandon it. After a brief fight however, Peach offers tea and the three drink, becoming friendly.

Ganondorf's Role
Ganondorf reprises his villainous role and helps the Subspace Army as a servant of Master Hand along with Bowser, who he later betrays and turns into a trophy with a Dark Cannon. It turns out that Master Hand was (literally) being puppeteered by the main antagonist: A villainous entity known as Tabuu. When Ganondorf sees this, he is enraged and charges at him, but Tabuu easily sends him flying backwards and turns him into a trophy. He is knocked into Master Hand, and in the process, severs the strings controlling him. Master Hand then tries to attack Tabuu, but to no avail, as he too is knocked into the ground and apparently rendered unconscious. Later, on the way to Tabuu, Bowser discovers the trophy of Ganondorf and begins to brutalize it as an act of revenge for his betrayal. Shortly afterward, he is discovered by Link and Zelda, who resurrect him. Initially responding with anger and a headache, Ganondorf joins them to help out in the final fight against Tabuu.

Toon Link's Role
Toon Link does not have a role and only appears if you enter a secret door in the forest after clearing the Subspace Emissary.

Enemies
Other than Goombas, Koopas, Hammer Bros. and R.O.B. all the enemies in the Subspace Emissary are completely original and made for the game.