Zack

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.

Kingdom Hearts Birth by Sleep
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.

During Herc and Zack's showdown, an army of Unversed appear in the city of Athens and Ventus goes to deal with them. Not wanting their friend to get hurt, Herc withdraws from the competition just one second before Zack does. By the time Zack arrives, the monsters are already defeated. Phil then arrives and tells them that part of a hero's important quality involves the will to do what is right and quick acting, and, since Zack withdrew after Herc, Hercules is once again "becomes" Phil's trainee. Though disappointed, Zack faces his defeat cheerfully.

During one of these tournaments, Terra arrives in the Coliseum and Hades tries to find a way to make Terra succumb to darkness. When Zack walks by, Hades uses the darkness in his heart to control him. When Terra reaches the final round, Zack becomes his opponent but is defeated. As Terra turns to leave, Zack gets up and attacks again, this time using the power of darkness and more powerful attacks. Terra wins again, freeing Zack from Hades control.

Later, he was seen asking Aqua out on a date. Aqua shakes her head and arms in embarrassment.

In the ending credits, Zack is seen leaning against the door to Olympus Coliseum while watching Phil train Hercules. A black feather flutters behind Zack, and he looks around in surprise. All that is then seen of him is a single feather drifting down where he once stood.

Appearance
Zack sports his original hairstyle of short, thick black spikes with bangs framing his face. His eyes are a bright blue. Due to his appearance in Olympus Coliseum, he wears armor similar to that of Hercules, though his is grey, as opposed to Hercules's orange. Other than this additional armor, Zack wears his SOLDIER uniform of two silver pauldrons, black gloves, a brown guard over his abdomen that is worn over the armor, two belts over the aforementioned guard, and his blue pants and turtleneck, significantly brighter than Zack's original navy-colored clothing.

Zack's brown, knee-high sandals also bear the vague design of his original black, knee-high boots, and he wears black socks underneath them. Small parts of his outfit have had swirls added to them and his physique is slightly different, likely to fit more with the style of Olympus Coliseum. Finally, Zack carries his original SOLDIER sword as a weapon. The SOLDIER's logo is seen both in his sword and in his brown guard, just above the belts.

Recent scans have also shown Zack to wear a Gladiator/Spartan style helmet in some instances.

Fighting Style
Zack is fought twice within Terra's story and once in Aqua's story. You must talk to Hades in the Coliseum Lobby to fight Zack. He is a very strong opponent and can be very difficult to defeat if not prepared properly. His attacks in the first battle do mild damage. These attacks include a spin-slash attack, a quick 3-hit combo, a jump ground attack, and a Dark Braver attack.

In the second battle, he is much quicker. His attacks have been powered up and can be very deadly. He keeps his four original attacks including two new ones, a high speed slash technique and a meteor attack. To keep up with Zack, D-Link with Ven for higher speed or D-Link with Aqua to have greater magical capabilities.

D-Link
Zack becomes a D-Link for Terra, Ventus, and Aqua after their separate encounters. While in link with Zack, they can perform powerful blows with increased speed as well as create wave beams to blow their enemies aside.

Origin
Zack first appeared in the NTSC, PAL, and International versions of Final Fantasy VII as a minor character, yet pivotal towards Cloud before appearing as a full-fledged character in the prequel, Crisis Core. Having wielded the legendary Buster Sword before Cloud, Zack was an aspiring 1st class member of the elite troop known as SOLDIER.

Trivia

 * Zack is the fourth Final Fantasy character to be introduced at Olympus Coliseum (following Cloud, Sephiroth, and Auron), and idiomatically the seventh Final Fantasy VII character to appear in Kingdom Hearts. Because Zack has been redesigned to be in the the same style as the residents of Olympus Coliseum, its possible that it may be his home world. If that is the case, Zack would be the first Final Fantasy character whose home world be one based off a Disney movie, rather than an original Kingdom Hearts world like Traverse Town, Radiant Garden, or Twilight Town.
 * The way Zack asks Aqua out on a date may be an allusion to how he does so to Aerith in Crisis Core: Final Fantasy VII.
 * Zack's tutelage under Phil to become a "hero" at a young age alludes his original counterpart under the tutelage of his mentor in Crisis Core: Final Fantasy VII with a dream of becoming a hero as well.
 * During the credits sequence, Zack leans against the door at the Coliseum just as he does at the end of Final Fantasy VII: Advent Children (Final Fantasy VII: Advent Children Complete).
 * Zack is the second Final Fantasy character to appear in the series with his own theme; a remix of the main theme of Crisis Core, known as Successor.
 * Throughout Kingdom Hearts Birth by Sleep, Zack can be seen doing squats, a well known hobby of his in Crisis Core: Final Fantasy VII.
 * Some of Zack's attacks are variations of DMW limits used in Crisis Core. These include Meteor Shots, Octaslash and Rush Assault. He also uses a variation of Cloud's Braver Limit Break, which greatly resembles the way Zack uses the Jump Materia in Crisis Core.

Zack