Android 18, originally a human named Lazuli, was forcibly transformed into a cyborg by the mad scientist Dr. Gero of the Red Ribbon Army. She is the twin sister of Android 17. Despite being called an android, she is a cyborg enhanced with bio-organic components and a perpetual energy reactor that grants her limitless stamina, superhuman strength, speed, durability, the ability to fly, and energy projection, while preserving her human biology including the ability to have children.

In most appearances, Android 18 displays a cool, confident, and often sarcastic demeanor. She is pragmatic, bluntly honest, and can be motivated by financial incentives, but she is fiercely protective of her family. Initially an antagonist who disregarded Dr. Gero’s orders, she later marries Krillin, and they have a daughter named Marron. Over time she becomes a devoted wife and mother, integrating into the group of Earth’s defenders. She participates in the Tournament of Power for Universe 7, defeats Ribrianne, and sacrifices her position to help Android 17 achieve victory. In Dragon Ball Z: Battle of Gods, she attends Bulma’s party and courageously intervenes against the God of Destruction Beerus, though she is quickly incapacitated. In Dragon Ball Z: Bio-Broly, she acts as a debt collector for Mr. Satan and engages Bio-Broly but is defeated. In Dragon Ball Z: Resurrection ‘F’, she stays behind to protect Marron at Krillin’s request, expressing admiration for his courage, and is later killed when Frieza destroys Earth, only to be restored when time is reversed. She can generate a protective barrier and use techniques such as the Destructo Disc.

In an alternate future depicted in Dragon Ball Z: The History of Trunks, Android 18 is a cruel, sadistic cyborg who, alongside her brother, terrorizes Earth and kills most of its defenders, including Gohan. This version delights in destruction, shows no remorse, and is ultimately obliterated by a grown Trunks.