Chaos Mode is a difficulty setting exclusive to Star Ocean: The Last Hope. Comparable to 4D Mode in Star Ocean: Till the End of Time, Chaos Mode is the hardest difficulty level in the game, harder than even Universe Mode. To unlock this difficulty, the player must beat the game on Universe Mode.
On this difficulty setting, all enemies have their stats increased by an average of 1.6 times their usual on Galaxy Mode. Their Rush Gauges also increase at a faster rate. To further compound the difficult, the targeting cursors that surround the player characters disappear. Blindsides are still possible, but they are more difficult due to a lack of knowledge about who is being targeted.
By completing the game on Chaos Mode, the player unlocks the XBox 360 Achievement "Chaos Conqueror", worth 70 Gamerscore points.