Sisters

''This article is about the Manga version of Sisters. For alternate pages referred to by this name, please click any of the icons above.''

Sisters (シスター, Shisutaa), is a title given to female humans who are aspiring to become Mamas. They are caretakers for orphans in the Premium Farms like Grace Field House. Sisters are former "orphans" who have proven to be capable of having children and have surpassed an insurmountable level of expertise on the daily tests as well as spent a lot of time of training. They need to keep up their hard work or they may also get killed. Girls born at the Premium Farms who live to the age of twelve are given the choice to either die or train to become sisters when they are shipped out. One must have perfect scores on their tests and a recommendation from their own Mama in order to be given this option.

System
At Grace Field, when a girl chooses to train to become a sister when they are shipped out, they are immediately sent off to train at Grace Field Headquarters and study what they have to do and know to keep a plant thriving. They are also given tips on how to take care of children, clean, sew, etc. We know this based on the various stereotypical "motherly" activities shown in both Krone and Isabella's training montage. However, as seen in the bonus chapter, Seeking the Sky of Freedom, most sister trainees are "rejected" (killed) during their training. Very few girls training to become Sisters actually get the position, and even fewer get to become Mamas. This is because the Grandma only chooses one girl per class to be given the position of a Sister, with all of the others being "rejected". As a result, all of the girls must compete with each other for the position. They can never trust anyone and they constantly live in fear, knowing they could be killed at any moment.

All girls training to become caretakers are artificially inseminated as teenagers. If they fail to become pregnant and give birth they will immediately be "rejected". The Sisters are supervised by a Grandma that chooses the top scorers to become Mamas. Most Sisters reside at Grace Field Headquarters for the rest of their lives. Their job includes preparing food and supplies that will be sent to the "orphans", caring for the zero to one year olds, and giving birth to more children to fill the "orphanages". They are never allowed to meet their children as they are taken away immediately after birth. The babies are also assigned false birthdays so that the Sisters cannot tell which baby is theirs. After completing their training to become a Sister, some girls are given the option to train to become a nurse or surgeon who delivers babies and surgically installs the Microchips into the hearts of young girls who are willing to become caretakers. Sometimes, when a Mama requests extra help, a Sister will be sent to live at one of the Houses to assist the Mama in caring for the children.

If a girl survives her training, proves herself capable of giving birth to children, and serves as a Sister for many years, she may one day have the opportunity to return to one of the Houses as a Mama. However, there are only five Mama positions (one for each plant) and therefore it is a very sought after position by the Sisters. After serving as a Mama for many years, a girl may even be promoted to Grandma, of which there is only one. Grandma is the highest position a human can achieve at Grace Field and thus, it is the most sought after position. Even after being given the position that they have fought so hard to achieve, the girls continue to live in fear. They believe that the only way to get a slightly better life for themselves is to compete with the other Sisters and Mamas and bring them down in hopes of taking their positions and making themselves look better in the eyes of Grandma and the Demons. They are very depressed and unhappy with their lives, but they manage to mask their despair in order to get their jobs done.

Microchips
Like all of the humans residing at Headquarters, The Sisters have Microchips implanted in their hearts that does not allow them to leave the farm. The Microchips are the method used by the demons to prevent caretakers from escaping. They are embedded into the hearts of young girls who are willing to become caretakers almost immediately after they arrive at Headquarters to begin their training. The Microchips are programmed to send an electric shock to their hearts which kills them immediately if they take one step outside of the farm. They are also programmed to send an alert to the higher-ups if their heart stops on its own for any reason. The surgery to install a Microchip leaves a giant vertical scar across the person's chest.

Appearances
Sisters can be seen with dresses almost identical to dresses of the English Victorian-era maid style. This is depicted as a long black base dress that goes beyond the ankles, a pure white apron that covers the front of the base dress, a pure white belt that wraps around the waist, and a pure white collar that tucks in under the turtle neck of the base dress. Some dresses also include a series of buttons along the neck-line.

These dresses are exact replicas of what Mamas are shown wearing. The dresses are depicted to look like maids possibly to represent the sisters and mamas endless service to the Grace-Field and Glory Bell factory. While training to become Sisters, girls are shown to be wearing a dark gray long sleeved, uniform shirt with long, dark gray sweat pants. They receive the official uniform after completing their training and becoming a Sister.

Trivia
Their Victorian-era maid dresses worn in both the show in manga by the sisters represent the everlasting service they must do in order to run from what seems like their own fate. They are supposed to feel like servants, doing whatever it takes to meet ends due. Or in their case, doing whatever it takes to avoid death. This creates all the young girls put in this situation to feel powerless and brain dead. As if their only purpose is to help the very farm that's enslaving them.