Co-Op Event 7: Battle of the Dark Sides
From SmashWiki, the Super Smash Bros. wiki
Battle of the Dark Sides (死闘、ダーク軍団, Fight to the Death, Dark Corps) is the 7th co-op event match out of a total of 21 in Super Smash Bros. Brawl. Player 1 controls Link, while Player 2 controls Samus. This is the co-op counterpart to the solo event Event 18: Dark Link Duel, but Samus has been added to both teams. King Bulblin is once again absent. Each player has 200 HP, and the event is completed by dropping both the CPUs' HP to 0.