Chaos is one of the executives of the Secret Society who had suddenly and unexplainably lost his memories and became completely insane. However, his position in the organization was still held and Chaos entered the second Toshinden tournament under the orders to eliminate the traitor Gaia. When the Secret Society had fallen in its conclusion, Chaos had managed to survive somehow and participated in the third tournament.
During the events of the fourth tournament, Genma possesses the shield once carried by Chaos, indicating a high probability that he was killed by him.