Defeating Neo Exdeath earns the player the "Warriors of Light" achievement in the mobile and Steam versions. If no one is KO'd by the end of the battle the player gains the achievement "The Real Letter."
Neo Exdeath is split between four body parts: the front is the horned humanoid, the top is the region between the red and canine creatures, the middle target is near to the grinning horned skull, and the back are the two skeletal figures.
Neo Exdeath attacks quickly and relentlessly, using a variety of status ailments, physical attacks, magic attacks, defensive spells, the almighty Almagest spell, and his dangerous Grand Cross attack.
Neo Exdeath's most dangerous attacks, Almagest and Grand Cross, have signs of being prepared beforehand. If Neo Exdeath begins to shake he is preparing to perform Almagest. If he says "The laws of the universe mean nothing!" and darkens in color, he is preparing to perform Grand Cross.
The Front section largely performs physical attacks, the Top section performs Grand Cross, the Middle section uses Almagest, and the Back section can perform Delta Attack. When only one part of the four is remaining, it will use Meteor on every turn until it dies.
The best strategy is to attack each section one part at a time. The Front section has the least HP, but should be focused on thirdly due to its lack of powerful attacks. For healing, the best strategy is to have a White Mage with Dualcast. Since this is the last battle, items (and gil if the party has Zeninage) can be used with reckless abandon, unless the player is playing the GBA, mobile or Steam versions and wants to do the bonus dungeon that opens after the game is completed. These versions' Gladiator'sFinisher attack can be used to easily damage Neo Exdeath. A Cannoneer'sDragon Cannon also does great damage (Blitzshot + Dragon Fang).
If the player is at a low level or is finding it difficult to beat the final boss, they may consider using this strategy: The party should have a character with the Mix ability and enter the battle with Exdeath's first form and mix a Hi-Potion with a Dragon Fang to cast "Dragon Power" on an ally and raise the character's level by 20 for the remainder of the battle. This may be cast as many times as needed to reach level 99. During this time a White Mage should be healing the party. Flare and Holy should now deal more than 6000 damage points. After defeating Exdeath's first form they enter the fight with the second form while still at level 99. If the player needs further help they can mix an Elixir with a Dragon Fang to cast "Giant Drink" which doubles the allies' maximum HP. Golem can be summoned to block Exdeath's physical attacks.
The cheapest method is to make the party all Mimes with one equipped with the Summon and Dualcast commands. The characters can summon Bahamut twice and keep miming each other. Alternatively, the player can choose to replace one of the Bahamuts with Curaga.
The battle is also fairly easy if the characters have mastered Ninja, Ranger, and Samurai. In the Freelancer class the character can equip Rapid Fire, and Zeninage. Having mastered Ninja all party members will already have Dualwield. The first form is easily defeated by using Rapid Fire five to six times and the second form is defeated by tossing gil. This should kill him before he has a chance to use his Grand Cross attack. The Rapid Fire can also be used in conjunction with Mystic Knight's spellblade with Flare.
Although it is overall not a good idea to use one-hit KO moves on bosses, the summon Odin's Zantetsuken attack can one-shot Exdeath's back portion, but only if used through the Magic Lamp; otherwise Odin will use Gungnir. Additionally, the Blue Magic spell Doom will also work.
When one part of the four is remaining, it will use the powerful spell Meteor on every turn until it dies. After destroying two parts of Neo Exdeath, it is better to split the attacks on the remaining two instead of killing one part only to avoid the constant Meteor attacks.