FRANXX

FRANXX are armor and control systems created by Dr. FRANXX to combat Klaxosaurs, usually piloted by children in boy-girl pairs. Those who can pilot FRANXX are called Parasites.

All FRANXX units are at the disposal of APE, the governmental body of this world.

After the galactic battle, all remaining FRANXX units became monuments in the Parasites' New Community.

FRANXX (mecha)
FRANXX units are bio-mechanical weapons built by Dr. Franxx and under the supervision of APE. They were built from klaxosaur skeletal remains that were excavated from Earth’s surface through a drilling process called S-Planning. They were specifically designed as defence arsenals against the klaxosaurs and are required for fertile male and female pilots to operate.

The FRANXX of Squad 13 feature certain similarities to the flowers after which they were named. They are the only known FRANXX that are uniquely designed as all other regular parasites use a standardized model and the 9's a standardized 9 Model.

Below are all the types of FRANXX units:

Parasites
Parasites are children who are trained and tasked with piloting the FRANXX with the sole purpose of protecting the plantations and the adult population from the klaxosaurs. The male parasite is the Stamen and the female is the Pistil.

The fact that Stamen is male and Pistil is female is directly reflected in the appearance of their uniforms. Stamen uniform have reversed "Y" symbol on its chests because male sex chromosomes are XY and Pistil uniform has "X" symbol on its chest because female sex chromosomes are XX.

This is also reason why FRANXX in Stampede mode has "X" shaped eyes.

The 9's are capable of battling as either Stamen or Pistil, as explained by 9'a to Hiro in Episode 23: DARLING in the FRANXX. That is also the reason for their uniforms being unisex and lack "X" or reversed "Y" symbols.

Below are the names of the current Pistils and Stamen of Plantation 13.

Positive Pulse/Negative Pulse
Postive Pulse/Negative Pulse ( ポジティブパルス／ネガティブパルス, Pojitibu Parusu/Nega Parusu), also known as P-Factor/N-Factor, are the designated signals of the stamen and pistil copilots when they attempt to synchronize. The stamen emits the positive pulse, which is red, and the pistil emits the negative pulse, which is blue. The higher the levels of the signals, the stronger the connection between the two grows and leads to a successful synchronization.

Paracapacity


Paracapacity (, Para Kyapashiti) is the numerical value indicating the degree of synchronization between FRANXX pilot and their FRANXX. There are three levels of paracapacity: high, median, and minimum range. The higher the paracapacity, better of a successful synchronization between the pilots.

According to Nana, a lack of compatibility between the co-pilots is common in the beginning. However, it is a necessity for a stable synchronization to be sustained or else it would be impossible to operate a FRANXX and the parasites would be considered candidates for pruning (removed from duty and disposed of).

If a pair’s paracapacity falls in the lower range, they are qualified to be pruned or the one who is deemed the cause of the lack of synchronization will be removed and thrown away. Although a pair’s partnership is not permanent regardless of their paracapacity, according to 9'α, the idea of changing partners, referred to as a partner shuffle, is considered impossible. However, this is given as a option for Mitsuru and Ikuno to prevent the former from being deemed eligible for pruning.

In the manga, Hiro realises Naomi had been pruned after she was 'sent back' after she and Hiro failed their final parasite aptitude test

Stampede Mode
Stampede Mode (スタンピード・モード) occurs when a pistil pilots a FRANXX without sustaining a synchronization with her partner. Because a FRANXX is more operational by its Pistil, their negative factor will rise rapidly and the FRANXX will take on a more beast-like appearance. This will negatively affect the Pistil's health if continued for long periods of time.

This phenomenon is first shown with Strelizia. After 081 dies, Zero Two is forced to pilot alone, transforming it into its beast mode. According to Nana and Papa, this wasn’t the first time Zero Two operated Strelizia in stampede mode. In another example, when Mitsuru refuses to fight and Kokoro tries to pilot Genista alone, the lip of Genista's hat opens, revealing sharp metal "teeth" and two orange crosses for eyes appear, forming a beast-like face (in the manga, Genista takes on more of a dragon form that consists of wings). In the manga, when Ichigo tries to pilot Delphinium alone, it took on a beast-like form almost identical to Strelizia’s stampede form.

Trivia
From the Darlifra TV Tropes Page:
 * The FRANXX units of Squad 13 have specific roles that make their teamwork more authentic than most seasoned parasites.
 * Delphinium: the commander-use melee unit
 * Argentea: the melee scout unit
 * Genista: the siege artillery unit
 * Chlorophytum: the ranged fire-support unit
 * Strelizia: the ace unit

FRANXX