Centuries ago, the Sorcerer Supreme who would become the Ancient One encountered the Dykkors, a demon race he ultimately banished to another dimension. They remained there until discovered and conquered by Dormammu. He led them in a failed invasion of Earth which was thwarted by Doctor Strange, and afterwards abandoned them. Later still, they returned to Earth when the Limbo-based demon N'Astirh opened a gateway to their dimension, using them to aid his own horde during a widespread attack on New York City. Many of the rampaging Dykkors were killed by the X-Men and other heroes. Though most surviving Dykkors were once again trapped in their home dimension, twelve remained on Earth. These twelve sought a human vessel to aid their new addiction to human blood, and confronted occult bookstore owner Norman Harrison. In return for killing others to supply the trapped Dykkors with the essence of human blood, Harrison was offered great power. He accepted, and the twelve demons merged with him. Soon after, he adopted the guise of Zodiak and used his new abilities to harness powers based on the astrological zodiac.
Gaining notoriety within the criminal underworld, Zodiak used his role as a hitman to double as his service to the Dykkors. He and mechanical duplicates he created in his likeness murdered several drug smugglers, leaving zodiac signs at the crime scenes. When one of the duplicates killed a young boy during a hit, it drew the attention of Ghost Rider (Dan Ketch), who sought vengeance. Ghost Rider found and defeated the fake Zodiak, but the real one made his presence known, taunting the vigilante before departing. Ghost Rider's search for Zodiak led him to a group of Zodiak's employees, the Seven. These beings were attempting to send four children to the Dykkors, but were stopped by Ghost Rider, Doctor Strange, and others. Strange and Ghost Rider traveled to the Dykkors' dimension to stop Zodiak's masters. Meanwhile, Zodiak attacked Strange's companions Topaz and Rintrah, gravely injuring Rintrah in the process. Ghost Rider and Strange returned in time to stop Zodiak, but Ghost Rider's false sense of this being another duplicate allowed Zodiak to escape again.
Ghost Rider found a man named Tim who knew of Zodiak, and sent him to give the killer a message. Lacking further duplicates, Zodiak tortured Tim, then forced him to wear a copy of Zodiak's costume. While Ghost Rider battled a demon-powered man called Suicide, Tim attacked the vigilante as Zodiak but soon revealed the truth and begged for help. As Tim died from Zodiak-inflicted injuries, the true killer assaulted Ghost Rider with a Dykkor-powered gun. When Ghost Rider destroyed the gun, Zodiak attempted to flee, but was knocked into the subway. Ghost Rider pursued him, and the two were joined in battle by Suicide. Zodiak took several hostages during the battle and revealed his mutated face to Ghost Rider. In yet another escape attempt, Zodiak taunted Ghost Rider for being unable to kill him. Enraged Suicide tackled Zodiak, sending both over the side of a bridge to be impaled on spikes. Though Suicide survived, Zodiak apparently did not. Ghost Rider and Suicide incinerated his body afterwards.
↑History taken from All New Official Handbook of the Marvel Universe Update #2, written by Jeff Christiansen, Sean McQuaid, Ronald Byrd, Michael Hoskin, Mark O'English, Mike Fichera, Stuart Vandal, Eric J. Moreels, Chris Biggs, Madison Carter, Anthony Flamini, Al Sjoerdsma, and Rich Green.