During the Shattered World Crisis, the Deadly Six were attacked and subjugated by Dr. Ivo "Eggman" Robotnik through use of the Cacophonic Conch, a magical shell horn that caused them immense pain. However, they were subsequently freed from this abuse by Sigma, an artificial intelligence from the universe of Earth 20XX. Grateful to their liberator, the Deadly Six forced Eggman to construct a new body for him, and then supported him in forcing Eggman to continue serving him with the aid of a similarly enslaved Dr. Albert W. Wily. The Deadly Six were promptly fitted with new armor to enhance their powers, but-demonstrating their treacherous nature-they then turned against Sigma and sought to take control of his growing empire. However, Sigma had anticipated this, and the armor promptly took control of its wearers, making them subservient to Sigma. The six were promptly dispatched to Earth 20XX's past and Mobius to recruit two more agents for Sigma in the form of the heroes Mega Man and Sonic the Hedgehog. Zavok, Zeena, and Zor traveled to Mobius' surface to capture Sonic, while Master Zik, Zomom, and Zazz went after Mega Man on Earth. (SU: #76; WUB: MM, StH)
Zik, Zomom, and Zeena were later dispatched to capture Eggman and Wily after the pair betrayed Sigma by arranging for M'egga Man and Sonic Man to cure each other. They were thwarted due to the interference of Xander Payne, who arrived on the Lost Hex and departed with the doctors via Genesis Portals that he generated. It wasn't long before the Zeti were given another task: leading Sigma's army of Mechaniloids against the Knothole Freedom Fighters, Robot Masters, Team Sticks, and Maverick Hunters as they arrived aboard the Sky Patrol. Despite being outnumbered, the heroes began making headway, but the Deadly Six responded by taking control of the robots from the present and future of Earth 20XX and forcing them to attack their comrades. However, their attack was eventually halted by the Egg-Wily Uppity Robot Scrambler Cannon, which freed the robots and destroyed the armor controlling the Zeti. They were then subdued and placed in the brig of the Sky Patrol. They were aboard the craft when it was destroyed by Sigma-2, but these events were later undone by the actions of Xander Payne. As a result, Eggman's invasion of the Lost Hex had never taken place, and he decided to postpone it, thus leaving the Deadly Six alone for the time being. (MM: #50, #52; SU: #77, #78; SB: #9; StH: #274)
- These events have not yet taken place in current narrative of the series, but are allegedly set to happen in the near-future.
At some point in the not-to-distant future, Eggman revisited his plot for the Lost Hex: upon invading the planetoid, he forced the Deadly Six into labor with the Cachophonic Conch. Under Zavok's leadership, the group traveled to the surface below and captured many Mobini for Dr. Eggman's experiments before returning home. (HCFS: #1)
- The Deadly Six originally appeared in the game Sonic Lost World.
- The design of the Deadly Six were inspired by the Oni of Japanese mythology, a race of demons.