Platinum Match

The Platinum Match is a hidden match in the US and European Versions of Kingdom Hearts and in Kingdom Hearts: Final Mix. It is unlocked at Olympus Coliseum if one clears the Hercules Cup. In it, the player fights the optional boss, Sephiroth.

Attacks
Description: Sephiroth's basic sword slash. Covers a long reach and has a wide arc, but can easily be deflected or jumped over.
 * Horizontal Slash

Damage: Medium~High (depending on exposure)

Description: The second Sora delivers the finishing combo, Sephiroth will vanish and flashes behind Sora to deliver a sword slash. (teleport period approximately about 1~2 seconds.)
 * Teleport Slash

Damage: Medium; blockable

Description: Sephiroth conjures three flame pillars around him. Using a special move like Ars Arcanum or Strike Raid will make Sora invincible to this attack, so it is recommended to use such techniques if you get caught in it. Sephiroth in turn is highly vulnerable while performing this move.
 * Stigma

Damage: Medium~Very High (depending on exposure)

Description:Sephiroth's trademark attack, used when around 70% of his first lifebar is shaved away. Drains Sora's HP to 1 and MP to 0. Can be interrupted if Sephiroth is hit while casting this attack. Sephiroth actually says "Sin Heartless Angel" before using this attack, so listen carefully for it. It is best to strike him before the halo around him completes, as this will interrupt the casting. If damaged while performing this move, Sephiroth will immediately use Stigma.
 * Descend Heartless Angel

Damage: Varies (no matter how much damage Sora has taken it can only reduce his HP to 1, and drains all his MP)

Description: Sephiroth does a frenzy of standing and leaping blows, then leaps up and does a finisher. Be wary of the last blow, because it does a great deal of damage. However, the blows are not entirely consecutive, so Sora can avoid many of them with properly timed guards and dodge rolls.
 * Omnislash

Damage: High~Fatal (depending on hits taken)

Description:Sephiroth will conjure dozens of dark orbs to surround him. The orbs serves as his shield and a distraction for a spinning sword slash. He often uses this moves many times in succession.
 * Shadow Flare

Damage: Medium~High (depending on exposure)

Description: Sephiroth's ultimate attack, his body emits a glowing white aura and he summons several meteors, which surround and orbit around him. A black hole later appears above his head and absorbs all the rocks, whom later releases a meteor homing Sora. The initial meteors can be avoided by running around them, and the last attack requires quite a bit of timing to dodge.
 * SuperNova

Damage: High~Fatal (depending on exposure)

Preparation
Sephiroth is easily the hardest boss in the original Kingdom Hearts and a great deal of preparation is needed. First, Strike Raid, Second Chance, Dodge Roll and MP Rage are absolutely essential. If possible, equip two MP Rage, meaning, unless you chose the staff, you'll have to be at Level 66 to earn the second MP Rage. Otherwise, being above Level 55 is best. Do not equip any other special abilities like Ragnarok or Sonic Blade. Equip any other abilities to boost Sora's power like Berserk and Critical Plus. Scan is useful, as it lets you see Sephiroth's HP and know when he's about to enter the next phase of the battle, but there are other signs to let you know this. If possible, equip the Ultima Weapon keychain, but otherwise equip weapons to boost Sora's MP and magic abilities. Oathkeeper, Lionheart or Lady Luck work for this by increasing Sora's max MP while still giving a strong attack. Also equip as many Elixirs as possible, or Megalixirs if you are out of Elixirs, and be sure to get Curaga from Aerith in Hollow Bastion. Finally, equip accessories to boost Sora's defense and HP. Gaia Bangles or Omega Arts work for this. Also note that all of Sephiroth's attacks except for Stigma count as the dark element, so equipping armor to resist that element will help greatly.

Phase One
For the first part of the battle, Sephiroth walks around the arena performing his Horizontal Slash and Stigma attacks, usually using the former when you come close. It is possible, by leaping towards him to avoid his Horizontal Slash, to hit Sephiroth with a combo, although you should Dodge Roll after hitting him to avoid his Teleport Slash. At this time, simply chip away at Sephiroth's HP with normal attacks, and heal when needed as MP Rage will restore your HP when you are attacked. It is important to note that while Sephiroth has six health bars, only five will show up, so your first attacks will only appear to do no damage, but actually are. Once Sephiroth's purple health bar is depleted, he holds out his hand and says "Come on", signaling he is entering his second phase of attack.

Phase Two
Sephiroth begins dashing around the arena very quickly, frequently using Teleport Slash. His first move upon entering this phase is to teleport and cast Heartless Angel. It is vital to hit him with Strike Raid at this time. The casting animation for Heartless Angel involves a halo appearing around Sephiroth. If you can attack him before the halo completes, you can stop the casting. Even if he successfully starts to casts it, continue to attack him. If hit while casting Heartless Angel, Sephiroth will go into a Stigma right away, giving you enough time to use an Elixir and heal yourself. If you can't hit Sephiroth in time to stop him, your only chance is to retreat while guarding and dodge rolling, as he runs towards you and attacks right afterwards with no time for you to heal. Sephiroth uses Heartless Angel periodically during this phase, so listen carefully for him to call the attack and stop him.

Sephiroth's other tactics are to simply run around the arena using Teleport Slash frequently. His other new move, Omnislash, hits very quickly and can be difficult to survive. You can cast Curaga during the attack, but he'll likely attack you and stop you before you can cast it. A better option is to hit him with Strike Raid when he calls out the attack, as you are invincible during Strike Raid and thus can become immune to his many slashes. Otherwise, repeatedly use Dodge Roll. The first hits of Omnislash can also be guarded. After using Omnislash, Sephiroth immediately teleports and uses Heartless Angel.

In general for Phase Two, always have at least two MP so you can use Strike Raid, and keep your HP high. With MP Rage, Sephiroth will be causing you so much damage, he'll be restoring your MP quickly so keeping your MP up should not be a problem. When Sephiroth is down to his yellow health bar, he will summon a green and black aura, signalling the final phase of the battle.

Phase Three
Sephiroth's final phase begins with him casting SuperNova. The meteors can be dodged with moderate difficulty. When Sephiroth begins the attack's end, target him and use Strike Raid - this will not damage him as Sephiroth is invincible while using SuperNova, but will make you immune to the attack's final hit. The final hit can also be dodged with proper timing by Dodge Rolling behind Sephiroth as he uses it. Sephiroth will also begin using Shadow Flare quite often and start erratically teleporting while spinning and slashing, leaving Shadow Flares in his wake. Although this seems daunting to avoid, during this time, Sephiroth is vulnerable. Instead, you can use Strike Raid, both avoiding damage and hitting him at the same time. This is perhaps the opportune moment to hit Sephiroth.

Sephiroth also retains all the attacks from his previous two phases. He still casts Heartless Angel, but no longer calls out the name of the move, making it vital to keep him targeted to know when he's casting it. Sephiroth also still uses Omnislash, and may even use it twice in a row. He still uses Stigma when interrupted while casting Heartless Angel.

Although this is easily Sephiroth's most dangerous form, the damage all of his moves can be minimized with deft dodging and usage of Strike Raid to exploit its temporary invincibility. Since he may still be landing hits on you quite often, your MP should be high throughout the phase, and healing yourself and attacking should be no trouble. As long as you can react to Sephiroth's moves quickly with the appropriate counter, you can defeat him. Focus on getting in hits whenever possible, while surviving his attacks using Curaga and Strike Raid and he will eventually be defeated.