as a young enemy, and a budding hero

Recently in Kingdom Hearts: Birth by Sleep, Zack was revealed as an NPC. He becomes an ally to the player of your choice in The Coliseum, but only after you free him from Hades. In order to free him, you have to fight him which leads to an extremely interesting opportunity, the chance to face him as boss. While Zack isn't all that difficult he does have some interesting attacks that are reminiscent of his DMW attacks in Crisis Core and some interesting abilities similar to those of Cloud and Sephiroth in the original (and I suppose second) Kingdom Hearts game.

Boss Fight Zack Round 1

HP: 600, Strength: 16, Defense: 9
Status Effect Vulnerabilities: Stun, Freeze, Ignite, Poison, Zero Gravity
Special Attacks: Swing, Dark Bolt, Jump
Elemental Weaknesses: None
Elemental Resistances: None
Reward(s): None/Deck Command Slot (Depending on the Storyline)
Notes: This round is fairly easy. Zack's attacks can perform a lot of damage however, they are easy to avoid. Zack's first special swing is easily blocked and you can gain get a counter attack for doing so. Dark Blot is slightly harder because while you can block it, you gain far more by avoiding it. Finally, jump is nearly impossible to block so it's far easier to stay out of range and wait until later.

Boss Fight Zack Round 2

HP: 600, Strength: 16, Defense: 9
Status Effect Vulnerabilities: Stun, Freeze, Ignite, Poison, Zero Gravity
Special Attacks: Swing, Dark Bolt, Jump, Hero's Pride, Meteor
Elemental Weaknesses: None
Elemental Resistances: 50% Damage from Dark
Reward(s): Deck Command Slot
Notes: All of Zack's previous attacks have the same effect; however Hero's Pride can cause several problems. It's similar to Sephiroth's Teleport Sword Slash but it has the added effect of dark energy. Hero's Pride does a lot of damage and is used often, so I would suggest avoiding it at all costs. Meteor is really just meteor shots, which if you've played Crisis Core you would know how to avoid. If not, don't worry it takes a while to charge up, so you can learn to avoid it.