After reaching the summit of Kefka's Domain, you must destroy Kefka once and for all.
Choose your Lineup
Before the battle begins, you will see a list of all of the characters that you brought to Kefka's Tower, and you must choose what order to put them in. The first four that you choose will be sent into battle, and if any character is in KO, Petrify, or Zombie status after a phase of the battle, the next character in the lineup will take his or her place for the next phase. However, if all four characters die before a phase of battle has ended, the game is over and you will have to try again from your last save point.
The first character that you choose will go in slot 1, the second character goes in slot 2, and so on. Keep choosing characters until you have put all of them in order. If you want to change the order, choose Reset to clear the list. When you are ready, choose End to begin the final battle.
The first part of the final battle is against the Statue of the Gods, which consists of three levels, often referred to as tiers.
Face/Visage
The first tier is known as Face/Visage. The face and the two arms can each attack separately, and all three must be killed before the party moves up to the next tier.
The Face
Be sure to kill the face either first or second. This way, you will prevent its final counterattack of Quake, which it only uses if it is killed last.
The face is weak to Fire and is unaffected by Earth. It can inflict Seizure/Sap, and can use R.Polarity/Reverse Polarity to move characters from the front row to the back, and vice versa.
The face will start using Dread/Dread Gaze once its HP is 10240 or lower. This move inflicts Petrify on the target.
As mentioned before, if you kill both of the arms before killing the face, then the face will use Quake when it dies. The face will not use Quake if either of the arms is still alive when it dies. Quake will not affect anyone who has Float.
Short Arm
The short arm of Face/Visage (i.e. its left arm) uses physical attacks, and will start to use VacuumWave/Razor Gale, a physical attack, when its HP is 10112 or lower. It is weak to Water.
Long Arm
The long arm of Face/Visage (i.e. its right arm) uses physical attacks and Shock Wave, a non-elemental magic attack. It can be killed with Doom/Death, or Break. It is weak to Wind.
Tiger, Tools/Machine, Hit/Power, and Magic
The second tier consists of four bosses. Tiger looks like a tiger's head, Hit/Power is the blue man sitting on Tiger, Magic is the man to the left of the woman in red, and Tools/Machine is the machine between Hit/Power and the woman in red.
At the start of this battle, cast Mute/Silence on Magic to prevent it from attacking. Try also casting Stop and Doom/Death on Tools/Machine. At that point, focus all of your attacks on Tiger, because it is the most dangerous enemy in this tier. Once Tiger is gone, kill Tools/Machine, then Hit/Power, and finally Magic.
Tiger
Tiger is weak to Ice and absorbs Earth. It will use S. Cross/Southern Cross and Flare Star, both of which deal a lot of damage to all characters in your party. Tiger will also use N. Cross/Northern Cross, which can freeze a member of your party. It will start using Doom Tusk/Zombie Fang when its HP is 11520 or lower. This move inflicts Zombie on one party member.
Tools/Machine
Tools/Machine is the mechanical object between Hit/Power and the woman dressed in red. Tools/Machine is vulnerable to Doom/Death and also vulnerable to Stop, so try casting Stop on Tools/Machine, then Doom/Death. If the Doom/Death spell is successful, Tools/Machine will eventually die. Otherwise, Tools/Machine is weak to Lightning. It attacks with Diffuser/Diffractive Laser, Grav Bomb/Gravity Bomb, Delta Hit/Delta Attack, Atomic Ray/Atomic Rays, Missile, and Tek Laser/Magitek Laser. When its HP reaches 11520 or lower, it will start using Absolute 0/Absolute Zero instead of Atomic Ray/Atomic Rays.
Hit/Power
Hit/Power is the blue man sitting on Tiger. Hit/Power is weak to Poison. It only uses physical attacks. When it dies, it uses the move 10 Hits/10-Hit Combo, which is a strong physical attack followed by nine regular physical attacks. Cast Safe/Protect on your party before you kill Hit/Power to protect yourselves from this attack.
Magic
Magic is the man to the left of the woman in red. It only attacks with magic, so it can easily be neutralized by casting Mute/Silence on it. It is weak to Earth.
Girl/Lady and Sleep/Rest
The final tier consists of a reclining man known as Sleep/Rest, and a woman's head and chest known as Girl/Lady. You can steal a Ragnarok sword from Girl/Lady and an AtmaWeapon/AtmaWepn/Ultima Weapon from Sleep/Rest.
Girl/Lady
Girl/Lady should be killed first, because she can bring Sleep/Rest back to life if he is killed, and also because she uses Pearl Wind/White Wind almost exclusively, which heals her and Sleep/Rest.
Girl/Lady has 9999 HP. She absorbs all elemental attacks and is "weak" to all elements, so all elemental attacks will heal her completely. Sleep/Rest often uses elemental attacks that target everybody, so he will be healing Girl/Lady at every turn. Girl/Lady will need to be killed with non-elemental spells such as Ultima and Flare.
Sleep/Rest
Sleep/Rest has no elemental weaknesses. On his first turn, Sleep/Rest will either do nothing or will attack with Merton/Meltdown, which deals Fire/Wind damage, or W. Wind/W Wind/Tornado, which reduces everybody's HP to 1/16th.
On his second turn, Sleep/Rest will either use a standard attack or cast Doom/Death.
When Sleep/Rest's HP is 10240 or lower, he will cast Meteo/Meteor, a non-elemental magic attack, on every turn, and if he is attacks, he will counterattack with either Meteo/Meteor or Train/Trine, a move that inflicts Mute/Silence and Dark/Blind on everybody. Use a Remedy to remove these status effects.
When Sleep/Rest is killed, he uses Calmness/Repose either once or twice. This move can be avoided by characters who have Image status. The Fenrir Esper can give everyone Image status.
Kefka
After the Statue of the Gods is defeated, you will face the final boss, Kefka. He has no elemental weaknesses, and is unaffected by Poison. He has 62000 HP and 38000 MP.
First Phase
He opens the battle with Fallen One/Heartless Angel, which reduces everyone's HP to 1. If you have a Megalixir, use one to bring everyone's HP and MP back to maximum. If not, use whatever healing spells/items you have at your disposal.
During the first phase of the battle, Kefka uses physical attacks, as well as Fire 3/Firaga, Ice 3/Blizzaga, and Bolt 3/Thundaga. He also uses Train/Trine, which inflicts Mute/Silence and Dark/Blind on everybody (use a Remedy to fix it), and Havoc Wing, a strong non-elemental magic attack.
Second Phase
When Kefka's HP is less than or equal to 32640, but greater than 7680, there will be a message on screen that says "The end comes... beyond chaos.../The end draws near...". After this, Kefka will use Goner/Forsaken, which is a very strong non-elemental magic attack.
Kefka will follow that up with Havoc Wing, Train/Trine, or Revenger/Vengeance, the latter of which removes positive status effects (such as Haste, Float, Reraise, etc.) from your party.
During this phase, if Kefka's HP becomes 30080 or lower, he will counterattack with either regular physical attacks or HyperDrive, a non-elemental magic attack that inflicts Seizure/Sap, but can be blocked by Runic.
Toward the end of this phase, when Kefka's HP becomes 10240 or lower, Kefka will start counterattacking with Ultima.
Third Phase
When Kefka's HP is 7680 or lower, the message "The end comes... beyond chaos.../The end draws near..." will repeat, and he will use Goner/Forsaken again. After this, he uses Meteor.
When Kefka has 0 HP, he is defeated. If you are playing the GBA or mobile versions of the game, be sure to watch the whole ending and save your game when prompted. Congratulations!