9'ζ, η, θ

 is a character in DARLING in the FRANXX.

Appearance
Zeta and her identical pistils have white hair, grey eyes, and silver masks. They are the third shortest members of the squad (the shorter ones being Alpha and Delta, respectively). Along with their teammates, the triplets sport the Nines' white-and-gold-emblazoned uniforms.

Personality
Very little is known of the triplets' personalities, other than that they are of one mind with their leader, Alpha. This compliance is manifested in episode 18, where one of them joins in the lopsided hand-to-hand fight against Zero Two.

Trivia
  9'ζ