Yin and Yang

Ying (ィン, Ying?) and Yang (ヤン, Yang?) were two loyal arrancar girls who serve Sōjirō Kusaka in the movie Bleach: The DiamondDust Rebellion. They appear to be twins, one of them has red hair while the other has blue hair. They are capable of using fire and electricity with the power of their respective zanpakutōs, of which one takes the form of a flaming sword with a red tassle on the bottom of the handle, the other taking 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.