Marrionette Louise "Mary" Test is one of the two tritagonists of Johnny Test. She is the older twin sister of Susan Test and the oldest of the test siblings. She is also the older sister of Johnny Test.

appearance

Mary has long curly red hair tied in a high ponytail and green eyes inherited from her mother. Her style of dress is very casual, especially compared to her sister's preppy style. She wears a pastel yellow shirt with a moon design. blue jeans, olive green sneakers with a moon design, white lab coat and a moon hairclip. Like her sister, she requires glasses to see, but she wears stylized frames with pointed tips. Mary has a yellow shirt with a light blue moon on it, long curly red hair, greenish blue eyes, crescent glasses and a moon-shaped barrette. She often wears baggy blue jeans and sneakers with a light gray lab coat. She sometimes wears a bright pink bikini and her disco outfit was a bright purple tank top with pink shorts and bright gray shoes.

Susannah Laura "Susan" Test is the younger twin sister of Mary Test . She is one of the two tritagonists of the series and the older sister of Johnny Test.

appearance

She has completely straight red hair  and has navy blue eyes and wears square glasses. She wears a shirt with a star on it and a yellow star-shaped barette in her hair. She one day hopes to meet a star. She is always seen wearing a light gray lab coat, black skirt and pumps with a light blue shirt with a navy blue star in it, and black Mary Jane shoes. She sometimes wears a greenish blue one piece swimming suit and her disco outfit was a greenish blue tank top with a black skirt, a greenish blue cap, bright greenish blue socks, and dark pink shoes. and black shoes. She first appeared in Johnny to the Center of the Earth. Susan has been shown to be less empathetic and sympathetic than her sister. Like her twin sister, Susan herbs a deep love and obsession for Gil. Bling Bling Boy has a huge crush on Susan but whenever he tries to get her to fall in love with him it always fails. Like her sister, she attends school at the Mega Institution of Geniuses. Susan is prone to believing in the more scientific and less science-fictional, which although gives scorn to her twin, Mary often proves to be right in the end. Susan seems to be less level-headed than her twin Mary, and Susan tends to be less conservative, as she speaks her mind much more than Mary. She is the younger of the two.

all characters are 18+