Chaos Elgo

Chaos Elgo is the final boss of Final Fantasy Dimensions. It is encountered in the World of Nil at the end of the game.

Story
Once the heroes reach the throne room inside the World of Nil, they come across Elgo who reveals himself to have been the Emperor all along. He harnesses the power of Nil in his attempt at becoming immortal, but after the party defeats him, he is consumed by the power and turned into the monstrosity that is Chaos Elgo.

The creature escapes between worlds through a dimensional portal, with the heroes in pursuit. They face off with Chaos Elgo in the final battle, ultimately defeating him and saving the world.

Strategy
It is recommended the party be level 60 or above before attempting this battle. The battle will be long, so the player should ensure they have a good supply of Dry Ethers and Elixirs. The Argy summon is helpful to counteract Chaos Elgo's Black Hole ability.

The battle starts off with Chaos Elgo casting Grand Wall, which deals roughly 3000 damage to a single party member. It will also use Eclipse to deal about 1000 damage to the party and randomly add Curse. Sometimes Chaos Elgo will counter with Gravity.

Begin by casting as many status buffs as possible, then unleash all your strongest attacks. After dealing a sufficient amount of damage, Chaos Elgo will transform into it's second state and cast Dark Flow, instantly killing the party. After a short cutscene plays, the heroes will be revived with their buffs intact. It's possible for Chaos Elgo to cast Black Hole, nullifying the status buffs, at which point it's recommended to recast Shell and Haste.

From this point on, Chaos Elgo will switch between three forms: the default form which uses physical and non-elemental attacks, the Dark form which uses black magic, status ailments and dark-elemental attacks, and the Light form which heals and casts buffs on itself while unleashing holy-elemental damage. The light and dark forms are resistant to their respective elements.

The boss can also use 10000 G's, which will reduce the entire party to single digit HP. When low on health, Chaos Elgo will begin to use Big Bang, which will deal around 4500 damage to the party along with sap. Ensure the party maintain high HP in the event of this.

Music
The song that plays during the battle with Chaos Elgo is titled "Inside the Swirl of Chaos" and was composed by Naoshi Mizuta.