Susan is a super genius scientist. She is the younger twin of her sister Mary. Susan has been shown to be less empathetic and sympathetic than her sister. Like her sister, Susan harbors a deep love and obsession for Gil.

Mary is a super genius and the older twin sister of Susan and also the older sister of Johnny. Mary has been shown to be more empathetic and sympathetic than her sister. Like her sister, Mary harbors a deep love bordering on obsession for the Tests’ next-door neighbor Gil Nexdor.