Zero Two (ゼロツー, Zero Tsū) is the main heroine and the deuteragonist of DARLING in the FRANXX. She is a human-klaxo Sapien hybrid and a member of the APE Special Forces, primarily fighting on the front lines.
Zero Two's personality is rumored to be dangerous, cold, and alluring as she grew up. Her outlook on life is quite cynical, so she didn't bother with a name since they are all meant to fight and die.
When people around her fail, she hardly bats an eye at it because, to her, it is just a fact of life that everyone dies. Zero Two always keeps people at arm's length with mocking humor, nihilism, and emotional detachment. Zero Two also freely talks about how much she hates society.
It is later seen that Zero Two is a very unruly, passionate, fierce-tempered, self-confident, smug, assertive, and carefree girl who hates to follow the rules set up by the adults.