Dark Link

Dark Link (also known as Shadow Link or Link's Shadow; in Japan, simply as Doppelgänger) is the evil counterpart of the hero of Hyrule, Link. He made his debut appearance as the final boss of Zelda II: The Adventure of Link, and has since made other appearances in other The Legend of Zelda titles. This shadowy being resembles Link exactly, except for the fact that Dark Link is completely black. Shadow Link is also a master swordsman, just like the original. Unlike most other enemies featured in the Super Smash Bros. series, Dark Link does not have his own trophy.

Super Smash Bros. Melee
Dark Link appeared in Super Smash Bros. Melee as the opponent in Event Match 18: Link's Adventure. In the battle, the player controls a red-clad Link, who has two extra lives. The fighter must defeat Dark Link, who also has two lives. The two swordsmen are fought at the Temple, with no time limit. This Event Match is a reference to the ending of Zelda II: The Adventure of Link, where a similar Dark Link served as the game's final boss.

Super Smash Bros. Brawl
In Super Smash Bros. Brawl, Dark Link returns in two Event Matches. The first, Event Match 18: Dark Link Duel, is similar to the match from Melee, but it is fought on the Bridge of Eldin instead, and is a stamina match rather than using lives. The second, Co-Op Event 7: Battle of the Dark Sides, is the same as Dark Link Duel, but with the addition of Samus Aran and Dark Samus assisting Link and Dark Link, respectively.

Versions of Dark Link also appear as palette swaps for both Link and Toon Link. Link's is based off the "interlopers" from The Legend of Zelda: Twilight Princess, whereas Toon Link's is based off Shadow Link from The Legend of Zelda: Four Swords Adventures.

Super Smash Bros for 3DS / Wii U
In Super Smash Bros. for Nintendo 3DS and Super Smash Bros. for Wii U, one of Link and Toon Link's other costumes include one reminiscent of Dark Link.

Super Smash Bros. Ultimate
Dark Link will reappear as an alternate costume for Link and Toon Link, while debuting as a new one for Young Link.

Trivia

 * Out of all the dark characters in the Super Smash Bros. series, Dark Link is the only one who has yet to receive a playable appearance.