Android 18 Character Facts

Android 18's petite form and beautiful face hides her massive strength. She has shoulder- length blonde hair, blue eyes, and hoop earrings in both ears. She keeps the left side of her hair behind her ear. When she is first activated by Gero, she wears a blue denim vest and skirt (with the Red Ribbon logo on the back of the jacket) with dark blue stockings, brown boots, and a black undershirt that has white and black striped sleeves. Later, she wears a black vest, a white undershirt, blue jeans with a golden chain, black gloves with a gold bracelet on the left one, and black flats with orange socks. When she is married to Krillin and living at Kame House, she wears a pale blue denim vest buttoned up, white 3/4 pants and black sandals. Later, at the World Tournament, she wears a black shirt, with black and white strips on the sleeves, blue jeans, red earrings, and black flats with orange socks. In Dragon Ball GT, she cuts her hair shorter and wears fashionable business attire. 
Initially cool and confident, 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" ( she replies "That it doesn't matter" before tossing the number at the World Tournament Announcer). Android 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.
Android 18 is originally a human, and the eldest out of her and her twin brother (the eventual Android 17).[1] The twins were notorious delinquents, who Dr. Gero would meet by chance while looking for fresh material for his experiments. He then kidnapped them and restructured them into Android 18 and Android 17.[2] She is the second artificial human, between her and her twin brother, designed by Dr. Gero to be created by fitting a Human with cybernetics. Gero's experiments on her, resulting in her transformation into a cyborg, do not impede her ability to reproduce, as evidenced by her giving birth to a healthy daughter, Marron.