Sienna

Sienna (シエナ, Shiena) is a character in the special one-shot chapter A Mother's Determination. Born and raised on an unknown plantation at Grace Field House, Sienna now works as a Sister at Grace Field Headquarters. Due to her age, Sienna is considered to be one of the house's "premium quality goods".

History
Sienna was born and raised as an orphan at Grace Field House at an unknown plantation. At the age of twelve she was shipped out and began training to become a Sister at Grace Field Headquarters.

Appearance
Sienna seems to have curly orange hair and green eyes. As a child, she wore the standard Grace Field uniform- a plain white long sleeved button-up shirt and white skirt along with brown boots. As an adult, she wore the standard orphanage uniform made for the plantations' Sisters, which consists of a black dress with a white blouse underneath it and a white apron over it. Her identification number, "53684", is tattooed on the left side of her neck.

Personality
Sienna is a very shy, modest and not very brave woman. Her only desire was "not wanting to die" and being a woman who never makes special requests, she turned out to be one of the most reliable "Sisters". Sienna is also an ambitious woman whose main goal is to climb the hierarchy, obeying Sarah and Isabella. She is also very intelligent, diligent, and dutiful, as she is one of the Sisters closest to becoming a Mama and she presumably got perfect test scores as a child. However, like all of the Sisters, Sienna constantly lives in fear. She believes the only way to get a slightly better life for herself is to compete with the other Sisters and bring them down in hopes of taking their positions and making herself look better in the eyes of Grandma and the Demons. She is very depressed and unhappy with her life, but she manages to mask her despair in order to get her job done.

Promised Forest Arc
In February 2046, a month after fifteen orphans escaped from Grace Field and Isabella was promoted to Grandma, four sisters, Matilda, Scarlet, Sienna, and Jessica are jealous of Isabella's new position and decided to team up to take her down. They decided to frame Isabella by forging suspicious communication data and planting it in Isabella's room. Then they plan to start a rumor about Isabella possessing the data so that when the Demons search Isabella's room and find the data, she will get blamed for it. While Scarlet and Sienna begin spreading the rumor amongst the other sisters, Jessica keeps watch and informs Matilda via a walkie-talkie that Isabella has left her room and it is all clear for Matilda to go in to plant the fake documents. However, Isabella is one step ahead of them and as Matilda enters the room she is shocked to find Isabella inside having tea with Sienna, Scarlet and Jessica.

All four sisters were visibly petrified that they had been caught and their fear only intensifies when Isabella takes the documents from Matilda and revealed that she already knew their plan. Fully expecting Isabella to report them to the Demons, the four sisters are shocked when Isabella instead tells them that she plans to destroy Grace Field and asks for their help in doing so. The sisters do not believe her at first, but Isabella reminds them that there is no true way to achieve a happy life at the farm. Even the Mamas and Grandma, the positions all the sisters strive for, live in fear, have to compete with each other, and are viewed as nothing more than food by the Demons. Isabella also tells them that she had been raising their children and Plant 3 and that they are alive with some of them being among the escapees. The sisters burst into tears upon finding out their children are alive and agree to join her, but only if Isabella gives them a collateral that ensures she will not betray them if the plan fails. Isabella agrees and gives them the note written by Ray which Krone found and gave to Sarah in an attempt to bring Isabella down. The note is a goodbye letter from Ray to Isabella which reveals Ray knows he is Isabella's biological son. That way if Isabella betrays the sisters, they can show the Demons the note and say Isabella let her children escape because one of them was her biological son.

Return to Grace Field Arc
On November 13, 2047, just before Emma and the other escapees returned the Grace Field, Isabella along with Matilda, Jessica, Scarlet, and Sienna decide to finally approach all of the other sisters with their plan to betray the Demons and Peter Ratri. Isabella uses the same tactics the get the other sisters to join them. Later that day, when Ratri has the escapees cornered, Isabella and the other sisters turn their guns on Ratri in order to save the children.

Human World Arc
Later in the Human World in 2049, Matilda, Jessica, Scarlet, and Sienna visit Isabella's grave and leave flowers by her gravestone. They thank Isabella for her sacrifice and tell her that because of her efforts, they are happy now.

Isabella
Like all the sister she is shown to be resentful towards her, but respects her, she also thought that Isabella was amazing ever since she was a girl and that she was scared of her because of the latter's performance; perfecting the physical and written tests, nonetheless she stood up with her saying they never had a Grandma like this and is shown to be grateful towards her.

Jessica, Scarlet, and Matilda
Sienna is friends with Jessica, Scarlet, and Matilda, and after Isabella became Grandma, they decided to team up to bring Isabella down. However, they could never fully trust each other because the Sisters were always competing with each other and could never know when someone might betray them to help themselves. But after Isabella recruits them to help her bring down Grace Field, they seemed to develop a closer and more trustworthy relationship with each other. Their relationship seems to improve even more after going to live in the Human World, as they no longer have to compete with each other and can just be friends normally.