Measure Heart

is a character introduced in Toaru Majutsu no Index, and featured in the sidestory Toaru Majutsu no Index SS: Biohacker Arc, from which her name was finally revealed. For a long time only known as the Girl in the Dress (ドレスの少女 Doresu no Shōjo?) or Measure Heart, she is a teenage girl who participates in "enjo kōsai" or compensated dating for money. She is an operative of SCHOOL, acquainted with the ways of the Dark Side of Academy City, and the second of the three Gokusai sisters.