Din's Fire is a type of magic in the Nintendo 64 video game The Legend of Zelda: Ocarina of Time. Rather than Nayru's Love or Farore's Wind, two other magical abilities in the game, this one will actually harm enemies. Once executed, Link will be surrounded in a ball of fire that would dramatically harm enemies. It should also be noted that Din's Fire is the only magic in the game that is needed, as it'll set torches in flames.
Din's Fire is an attack performed by Princess Zelda in the Super Smash Bros. series, debuting in Super Smash Bros. Melee and later returning in Super Smash Bros. Brawl for the GameCube and Wii respectively. The move is Zelda's side B move, which when executed will cause Zelda to release a ball of flames. You'll be capable of controlling where it goes, though not entirely. Once the ball is close enough to one of your opponents, you'll be able to press B to make it explode.