Red, which symbolises passion, danger, and excitement. This reflects Zero Two’s dark past as the ‘Partner Killer’, her rebellious attitude, and the intense love she and Hiro share.
Blue, which symbolizes loyalty, leadership, and trust. This reflects Ichigo’s status as Squad 13’s leader, her dedication to the team’s survival and welfare, and her close friendship with Goro.
Green, which symbolizes fertility, growth, and dependability. This reflects Kokoro’s dream to become a mother and her close relationship with Futoshi, who wants to protect her but learns to put her happiness over his own, and later Mitsuru, who learns to lean on others and shares Kokoro’s perspective on the future.
Purple, which symbolizes mystery, sensitivity, and moodiness. This reflects Ikuno’s secret regarding her sexuality, Mitsuru’s issue with trusting others, and Futoshi’s dedication to doing his best despite his sensitivity.
The standard FRANXX model is dark grey and slender with yellow goggles. It wields a spear which can shoot orange harpoons made out of magma-energy. The harpoons are also capable of emitting powerful electromagnetic energy used for busting Klaxosaurs.