- "I will exterminate all humans with their own weapons, and...I WILL KILL YOU!"
ZED (ゼド Zedo ) was a bioterrorist who masterminded a zombie outbreak in Woodside City. He sought avenging his parents, who were killed and used for UDS (Undead Soldier), a government effort to use the dead as military weapons. He took control of the project, spreading a virus throughout the city; ultimately, he planned to release the powerful UDS in his body, the "God of Destruction", to eradicate humanity and fulfill his revenge.
ZED's parents were involved in the UDS (Undead Soldier) project, a government top secret plan to use the undead as military weapons. However, his parents were killed by another scientist, Gil Breitling, who then used their bodies as experiments. ZED has since swore revenge against all humans by killing them with their own weapons. Possessing supernatural abilities, ZED houses a powerful UDS in his body that he calls the "God of Destruction", which he plans to release to kill off all humans and avenge the death of his parents.
Unleashing the virus that turns the populace of Woodside City into zombies, he is pursued by AMS agents Linda Rotta, Rikiya Busujima, and Stick Breitling, Gil's son. He leads them in a dangerous and bloody game of cat and mouse, taunting them throughout their hunt with mixed messages.
During the outbreak, a young girl named Yoko arrived with her boyfriend in hopes to see some zombies in action, but her boyfriend fell prey to the undead. While she attempted to escape, ZED approached her with a floppy disc to give to the agents, fooling her into thinking she would be paid for it. When the agents arrive, ZED delivers a message congratulating them while informing them of the disc's whereabouts, ending the message mockingly declaring his love for all humans. The agents find Yoko in danger and retrieve the disc. Exploring its contents, a bald and scarred avatar of ZED appears, claiming he is not their enemy before showing them three cards to choose from. The message ends telling them they might understand if they survive long enough.
The agents finally encounter ZED in person at the city's chemical plant, but he merely insults them before the place explodes. After the agents stop a train that is carrying the virus from crashing, ZED reveals his plan to release the God of Destruction and kill all humans. Gas is released in the room, which ZED alone is impervious to. He tells Stick Breitling that he will suffer the most before the agents lose consciousness.
ZED reappears before them in a large mansion, informing them of the UDS project, his parents' involvement and their death at the hands of Stick's father. He then sends the agents into the underground base where he plans to kill them himself. There, he tells the agents that he holds the God of Destruction in his body and plans to release it, and after killing them he will be reunited with his parents. Defeated, the God of Destruction is released from his body, a powerful UDS called Black Magician Type 01. After a final grueling battle, the Black Magician is defeated and destroyed.
Immediately after his defeat, the agents find themselves in a desert during the sunrise. As they reflect on the truth of what ZED had revealed, they are picked up by a helicopter piloted by AMS pilot Marco Cloud, who informs them, "Now he's highjacked a ship!" The agents, realizing they still have much to do, go on to their next battle.
If she was saved earlier, Yoko is then shown waiting impatiently in the same warehouse she was found in, cursing ZED and saying he'd better return with her money.
ZED confronts the players in the final stage as the penultimate boss. Shown to possess the abiltity to teleport and levitate throughout the game's story, he takes full advantage of these abilities in the fight against him. His primary attack is charging and striking the players with glowing energy from his hands, and even wields a handgun in each. He is also able to form a shield that protects him from attacks and inflicts damage if the player touches it. Because of this, ZED will often chase the player and use it when he is close enough. He also uses it if he takes too many hits within a short time period, so hand-to-hand attacks should be exercised with caution. His most powerful attack is a laser that he shoots from high above.
The Black Magician possesses all of ZED's moves (with the exception of the hand guns) as well as his own, and his attacks are faster and more frequent. At almost 50% health he will summon powers based on the card chosen in the first stage of the game: Red will grant him the ability to shoot rapid fireballs at the players, yellow will enable him to cover himself in electricity, and blue will allow him the ability to summon enemies.
- Black Magician's battle grunts are actually some of ZED's voice clips reused, except with a sound filter added in. That said, ZED and Black Magician share the same voice actor.
- The game's ending has confused some players as to whether ZED somehow survived his defeat, with Marco declaring "he" highjacked a ship when he was just destroyed.
- Zed is also a derogatory term for zombies used by humans in the novel, World War Z, written by Max Brooks in 2006.
- The Curien Mansion is used as ZED's base of operations. However, the interior areas of the mansion are quite different.
- In the game's opening, a letter from ZED is shown, as well as a photo of a child with two adults, presumably ZED and his parents. The adult on the left side bears a resemblance to Thomas Rogan.
- The final boss Black Magician is based on a certain recurring final boss from the main series. Although they share some visible similarities, Black Magician possesses wings, a visible heart, and open eyes.
- Black Magician is not identified with a UDS number like the other bosses in the game, but with a "Type" like those of the main series.
- Black Magician appears to kill the players should they run out of time.