Mistilteinn was created as part of the plantation project by APE to seek refuge from the Klaxosaurs and the desertification of the planet. As Dr. FRANXX’s research of the parasites grew, it was decided that Mistilteinn would be used as a quarantine zone for the parasites in order for them to develop the emotional responses required to pilot the FRANXX.
As proper procedure to keep the parasites in order, Mistilteinn is equipped with surveillance cameras throughout the area. Mistilteinn is full of woods and a few lakes
, and it contains a few animals, such as birds and cats. The weather is controlled through a sprinkler system located in the floral glass ceiling. Squad 13 was stationed at Mistilteinn after their discharge from the Garden and they lived there for nearly a year before a Lehmann Klaxosaur attack left the plantation in ruins. Mistilteinn survived the destruction but, as it was expected to collapse soon, the parasites were deported to the Bird Nest.
Squad 13 would briefly return to Mistilteinn shortly after to gather soil to grow crops.
The boarding house (寄宿舎, Kishukusha) is the residence of the parasites. It is a three-story house and is closely monitored with surveillance cameras in every room. The house is based on a European style and it is hinted that it was built as an inspiration from a mansion in the Abandoned Town, due to the two having strong similarities.
This building is where Nana and Hachi work to monitor the parasites. It is a big glass building in the middle of a water body and the only way to reach it is by crossing the bridge. Hiro was given permission to stay in Mistilteinn here. Also, the 9's were looking through the Baby Book in a room in this building. More importantly, this building contains the elevator for accessing lower levels of the plantation, namely the Inner City and Parking Dock.
The greenhouse is in close proximity to the boarding house and it where Kokoro takes care of the plants. Mitsuru also uses it as a hiding spot to be alone but the two later use it to spend time together.
- In the manga, Mistilteinn and the rest of Plantation 13 is destroyed by 001, who, with the use of a stolen 9 Model, merged with with Star Entity.
- Mistilteinn means ‘mistletoe’, which is a hemiparasitic plant that draws nutrients from its host. It is an angiosperm (flowering plant with seeds enclosed in an ovary, as compared with a gymnosperm which has seeds not enclosed in an ovary like a pinecone) that produces berries for means of reproduction. In western tradition, mistletoe is hung during the Christmas holiday and couples that pass underneath it together are expected to kiss. Mistletoes are said to represent romance, fertility, and reproduction
- It also derives from the name of Hrómundr Gripsson's sword in Hrómundar saga Gripssonar, a legendary saga from Iceland.