Zack is a character in Kingdom Hearts Birth by Sleep that appears in Olympus Coliseum and is the only Final Fantasy character to appear in the game (other than the Moogles). Zack strives to be a warrior, teaming up with Ventus to fight off the Unversed. Zack meets Hercules through this Unversed attack, becoming friends with Ventus and harboring a possible crush on Aqua or just flirting with her.
 Zack appears in Olympus Coliseum looking for Phil, who is known for training people into heroes and hopes to become his trainee. He meets Hercules and Ventus during an Unversed attack and shows his skill in front of Phil. Since Phil only trains one trainee and already has Hercules, he "decides" to form a competition between the two boys to help make his decision: Hercules or Zack.