Duon (SSBB)

Duon (, Duon), is an unplayable character in Brawl and only playable in Boss Battles via hacking. It's unvoiced, letting out mostly mechanical sound effects.

When playable, Duon's power level scales with the difficulty setting chosen for Boss Battles. Uniquely, contrary to its appearance as a boss, it does not need to switch faces to use either side's attacks, and can fire projectiles with relative impunity while covering itself with strong close-ranged attacks. This makes Duon a very fierce opponent and among the strongest of the Brawl bosses.

Attributes
Without the restriction of side switching, Duon becomes an extremely imposing threat, capable of launching as many projectiles as desired. Additionally, because Duon's body is considered to be a solid object, characters can launch into and tech on it, which can even create combo opportunities, and Rotating Attack can hit players stuck on top of it for massive damage. Duon's attacks are shockingly fast on Brawl boss standards as well, giving Duon some minor reactive ability with moves like Bomb Drop. Arguably one of Duon's most standout traits, however, is Triple Beam, which cannot be reflected or absorbed. Because of how well it tracks, Triple Beam allows Duon to edgeguard opponents, something few Brawl bosses on platform stages are capable of. When used alongside Bomb Drop, Duon can create a sort of obstacle course that is very difficult to stop, making it vaguely capable of camping. These can be complemented with its head bash attack to catch opponents as they fly into Duon. Duon is also capable of ledgetrapping opponents with ease using Rotating Attack, invalidating tether recovery with ease.

Duon does have some flaws, though. Its Homing Missiles can come back to hurt it and deal massive damage regardless of difficulty, almost KOing it on lower difficulties and dealing around a third on Intense. While strong, when using this move, Duon can't dash or jump without extreme precision; otherwise, it will crash into them. The lack of Triple Slash also means Duon doesn't have a direct way to attack the middle of the stage outside of its dashing attack (/), which can be problematic against agile opponents like or. Additionally, Duon suffers from the trademark issues of all Brawl bosses: It is very easy for damage to be racked up by moves like 's Rock Smash and repeated Vegetable z-drops from, and with all its attacks being decently slow and reactable, it's capable of taking extreme punishment for misinputting. Thus, while arguably the strongest boss character when playable, Duon is kept firmly in check by its nature.

Moveset
Like all bosses, Duon's moves are inputted using a set of commands with a GameCube controller, chiefly with the D-Pad. Move names are taken from the Japanese strategy guide for Brawl. Damage varies by difficulty, the following being taken from the game's files. Unlike its boss appearance, Duon cannot use its side switch or Triple Attack; however, it will side switch automatically when using a move.

Codes
Like all Brawl bosses, Duon can be accessed using a Gecko code that enables debug mode controls for Player 3 in Boss Battles. It is encountered randomly without additional external modifications, meaning other bosses need to be defeated or forced to self-destruct with their own codes to reach Duon's stage. The following codes are for the NTSC-U version of Brawl and both codes must be on.

In competitive play
Because Duon is only playable through hacking, it's banned by default in all competitive Brawl tournaments. While some boss characters have arguments to be legalised, Brawl's bosses have unique challenges that make them particularly unlikely cases. They do not conform to the usual ruleset, are exclusive to Boss Battles and thus their specific stage, are subject to Boss Battles's random boss selection without further modifications, and have varying difficulty levels that would require rulings to decide on them properly. This boils down to a very clunky experience that would likely end up delaying tournaments due to the length of time it takes for them to be set up. Furthermore, 's Grapple Beam can reset the controls of Brawl bosses, which could cause further ruling issues. Ergo, Duon has seen little to no competitive experimentation outside of casual matches.

In The Subspace Emissary
Duon appears as a boss at Battleship Halberd Bridge in The Subspace Emissary, and is shown to be a being created through numerous Shadow Bugs extracted from merging together. It's the sixth boss of the game and fought by, , , /, and. It later reappears in The Great Maze with reduced health.