
Chaos is an Esper from the world of Ivalice. The Esper of Wind, he represents the Zodiac sign of Taurus, the Bull. Chaos has two large horns on his head, similar to those of a bull. From his power of Wind, his color sign is Gray. He is also referred to as the Vrishabha Ascendant, which is the Sanskrit name of its Zodiac sign as used in Jyotish (Hindu) astrology. Chaos takes his name and appearance from the final boss of the original Final Fantasy, Chaos. Their stories are similar too, both being caught in an endless cycle of life and death. The four swords surrounding Chaos most likely represent the Four Fiends of the original Final Fantasy, especially since, during his ultimate attack, each sword glows red, yellow, green, and blue, representing Marilith of Fire, Lich of Earth, Tiamat of Wind and Kraken of Water, respectively. Also, when the swords drop (see Tornado's animation), the green (Wind) sword is the last to drop, given that Chaos is Wind-elemental here.
Chaos is located deep within the Necrohol of Nabudis. To reach him,
the party must complete the "Waterway Haunting" and "Lost in the
Pudding" hunts. After doing so, you must complete the "Nabreus's Medal"
sidequest that eventually leads into the Necrohol of Nabudis. Defeat the
optional bosses, Fury and Humbaba Mistant, to unlock the path to Chaos. This
Esper adjusts well to any situation. It bases its attacks on the enemy's
weakness, so it always hits the opponent hard where it hurts the most.
Chaos enters battle with Reflect on, which makes it difficult to heal
him when the need arises. Equip and Opal Ring before summoning him to
prevent this from being an issue.