The Final Fantasy VII swordsman who appears in Olympus Coliseum tournaments in the first Kingdom Hearts is Cloud Strife.
In the original Kingdom Hearts, Cloud is portrayed as a mercenary drawn into the conflict surrounding Hercules and Hades. Hades hires him to eliminate Hercules, promising information about Cloud’s rival, Sephiroth. Sora encounters Cloud at Olympus Coliseum, where the character can become part of the world’s tournament and battle content.
Cloud’s appearance is based on his Final Fantasy VII design, but Kingdom Hearts gives him a different role and backstory. The game also places other Final Fantasy characters in its setting, including Squall Leonhart—known as Leon—Yuffie, and Aerith. That group often causes confusion because Leon is another prominent swordsman and fighter encountered by Sora.
Cloud should not be confused with Auron, who appears in Kingdom Hearts II at Olympus Coliseum, or Zack Fair, who appears in Birth by Sleep. Those characters belong to different Kingdom Hearts entries and do not change the answer for the first game.