Dark Link is a completely black doppelgänger of Link that appears in multiple Zelda titles, including Zelda II: The Adventure of Link, The Legend of Zelda: Ocarina of Time, and The Legend of Zelda: Four Swords Adventures. His origin is shrouded in mystery, sometimes often believed to be a creation of Ganondorf. Dark Link's strength and abilities differ in the games he has appeared in. In some games, he appears to know every single technique Link knows or has learned and can effectively match and counter his attacks, while in other games he is capable of using Link's items as well. Four Swords Adventures features a variant of the character known as Shadow Link, mass-produced shadow copies of Link that cause havoc wherever they travel, which in turn, frames the true Link for crimes he had not committed. Coincidentally, the Dark Link events in both Melee and Brawl are Event 18.
In Melee, Dark Link is fought by Link in Event 18: Link's Adventure, but appears nowhere else. Aside from the black texture, he is identical to Link. Since Dark Link is simply Link with a texture swap and the removal of a voice akin to a Metal Box, the texture can be applied to any character with the Debug menu.
Dark Link appears as an alternate costume for Link. This design is based on a cameo appearance of Dark Link in Twilight Princess. There is also an alternate costume for Toon Link known as Dark Toon Link. Also, Dark Link reprises his role as the enemy of an event: Dark Link Duel. Strangely, the Dark Link in said event is shown as being completely black, like in Melee. Even stranger is that the Damage meter icon uses Link's costume swap Dark Link.