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 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.

However, deep down, Kokoro holds back a myriad of feelings, being somewhat dishonest with most around her, specially Futoshi whose feelings she doesn't reciprocate, to the point she deems herself a bad person for doing so. Kokoro felt bad at not being honest with Futoshi and breaking their promise, and praised Mitsuru for being so honest to others.

Since Kokoro's finding of a certain book, which she kept hidden from the others, it looks like she is interested in Pregnancy and Childbirth, even wondering why humans stopped having babies. Furthermore, Kokoro treats the greenhouse's plants as if they were children, later doing so to a doll she made herself.

Her former FRANXX partner is Futoshi, and now she has formed a partnership with Mitsuru.

History
Like the others, she was raised in the Garden with the other parasites and went through the same amount of training.

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.

Despite their interactions, it is revealed by Episode 11 that Kokoro seemed to hold back her true feelings with Futoshi, showing that she did not feel the same as he did. Later, this led her to breaking their promise and switching partners, devastating Futoshi. However, Kokoro admits feeling bad about it and tells Mitsuru that she is a bad person for having done it.

By Episode 12, Kokoro has demonstrated no further aprehension of what she did, although, she seems to be on good terms with Futoshi.

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
Kokoro is the first to notice that something is still wrong with Mitsuru, after he tried pilotting with Zero Two. From there on, they have random walk-ins with one another mainly inside the greenhouse. Despite his aloof demeanor, she offers him help, but, he refuses it and sees it as Kokoro is pitying him.

When exploring the abandoned city, Mitsuru tells everyone that he can't look after all of them. Yet, nevertheless, he was the one to find Kokoro, who had wandered off on her own, and save her from being injured from falling debris. Despite seeing that Kokoro found a book and is taking it, Mitsuru keeps quiet about it and reminds her to not go off on her own. Even later on, Mitsuru says that the book is her matter, and not his, so, she shouldn't worry about him revealing its existence.

Kokoro shows great interest in Mitsuru, initiating conversations and topics with him, whenever they meet at the Greenhouse. She talks about plants and tells him their many names and meanings, and also talks about human having children, afterwards.

When the boys and girls start a "gender conflict", due to the events of Episode 08, Kokoro wonders if he is truly okay with talking to her and, just like Mitsuru, shows no interest in taking part of the "fight". However, unlike Mitsuru, she is not honest about it and praises him for being so open about his opinion.

By Episode 11, Kokoro shows further interest in Mitsuru, even going as far as to break her promise with Futoshi and become Mitsuru's partner. Despite Mitsuru's insistence that she was only doing it out of pity, Kokoro manages to talk it out with him and convince him to trust her and the others much more.

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