Zero Two

Over time, Zero Two developed romantic feelings towards Hiro. However, her animalistic determination to become fully human, along with Hiro's apparent fear of her increasing feral characteristics resulted in the couple briefly drifting apart. When their relationship as partners began to take a turn and slowly crumble, they realized their forgotten memories of their meeting during childhood. The two chose to sacrifice their lives in order to safeguard and ensure the survival of humankind.