Yin and Yang

Yin and Yang were two loyal arrancar girls who serve Sōjirō Kusaka in the movie Bleach: The DiamondDust Rebellion. They appear to be twins, of them Yang has red hair while Ying has blue hair. They are capable of using fire and electricity with the power of their respective zanpakutōs, of which Yang's takes the form of a flaming sword with a red tassle on the bottom of the handle, Ying's takes the form of a whip with a blue tassle on the bottom of the handle. They were sent to steal the King's Seal by Sōjirō in order to destroy the Seireitei. It is unconfirmed whether they were naturally-evolved like the Privaron Espada or if they were artificially-evolved through use of the Hōgyoku by Aizen.