Kokoro

Kokoro (ココロ) is one of the main characters in DARLING in the FRANXX series. She's a Parasite with codename "556" of Thirteenth Plantation, where she's partnered in boy-girl pair with Mitsuru to pilot a FRANXX called Genista. Her original partner was Futoshi.

Appearance
A beautiful girl with long, wavy, ashen blonde hair and rich blue eyes. She wears a lacy blue headband to keep her hair out of her face. When piloting Genista, she wears a white bodysuit with light green accents, and keeps her hair in a braided ponytail.

Personality
A very very nasty bitch, she is mean to mah boi futoshi

History
A very gentle soul with a kind and optimistic personality to match. She doesn't speak too often, but when she does her words are well thought-out and meaningful. Her former FRANXX partner is Futoshi, now her Partner is Mitsuru. Since her finding of a certain Book, It looks like she is interested in Pregnancy and Childbirth.

Futoshi
She gets along exceedingly well with her partner, comforting and complimenting him. During their first time in Genista they flash each other a thumbs up in the cockpit before beginning, and Kokoro reassures him he did a good job as they take their first steps.

They seem to have, as Zorome describes, a "lovey-dovey" relationship. In Episode 05, Kokoro offers Futoshi the seat next to her when Zero Two takes his spot, and she then hand-feeds him toast, imitating what Zero Two is doing to Hiro.

Miku
Miku tends to talk with her the most, with their dynamic being with Miku being the energetic of the two while Kokoro is the soft spoken.

Mitsuru
very nasty bitches

Etymology
Kokoro's nickname may use some of the numeral's readings from her real name "Code:556": ko, an alternative spelling of "5" and ro as in 6.

Kokoro is also the Japanese word for "heart".

Quotes
"I believe in you, Mitsuru."

- Kokoro