C 18 (人造人間１８号, Jinzōningen Jū Hachi-Gō), Lazuli (ラズリ, Razuri) when she was Human, is the twin sister of Android 17 and Dr. Gero’s eighteenth android creation, designed to serve Gero’s vendetta against Goku. While her interests do not initially deviate from this expectation, C 18’s curiosity to activate Android 16, in spite of Gero’s orders not to do so, leads Android 17 to take it upon himself to murder Gero. C 18 later becomes the wife of Krillin and the mother of their only daughter, Marron.
Initially cool and confident, C 18’s sarcastic humor later becomes the most striking trait of her personality. One example of her sarcasm is demonstrated when Goku takes notice of her assembly with the Z Fighters at the 25th World Martial Arts Tournament, leading to the retort “Look, he noticed. How cute.” (in Japanese she says “Took you a while idiot!”). Shortly after this, she is asked by the World Tournament Announcer if her real name is legitimately “No. 18”, to which she responds “My father was pretty dull” (in Japanese, she replies “That it doesn’t matter” before tossing the number at the World Tournament Announcer). C 18 still exhibits some of her sensitivity, especially towards her twin brother. This is in stark contrast to her alternate self from Future Trunks’s timeline, where she is a murderous sociopath who cares for no one but herself and her brother. In the Game Boy Advance game Dragon Ball Z: Supersonic Warriors, C 18 is hinted to dislike driving solely because of Android 17’s insistence in driving around aimlessly without anything better to do.