Grandma

Grandma (Japanese: グランマ, guranma) is a title given to a female human working for the Demons, who is hardworking and has proven to be capable of raising orphans in the Premium Farms like Grace Field House. She is a previous "orphan", Sister, and Mama who has surpassed an insurmountable level of expertise in Litany Exams and has undergone hours of training. "Grandma" is the highest ranking position a human can receive at Grace Field House. The grandma gets her own private room at Headquarters and overseas Grace Field farm. There is only one grandma at each Premium Farm and thus is a highly coveted position. Her job is to supervise and train new girls to become Sisters and then Mamas. The Grandma also decides who gets a position as a Sister or Mama and who is "rejected" (killed) during training. She will also take in daily reports through the Mama's radio and alerts the Mamas of any changes or upcoming shipments. Despite her high ranking position and control over the farm, the Grandma is still looked upon as nothing more than food by the demons, and will be fed to high ranking demons upon her death. Like all of the humans residing at Headquarters, the Grandma has a chip implanted in her chest that does not allow her to leave the farm. If she leaves farm property, she is immediately killed using the chip implanted on her heart. The Grandma is not changed unless she passes away or the Demons decide that she is not qualified for the position anymore and kill her.

Appearances
Their outfit consists of all-black long dress with puffed sleeves and black collar and buttons. Different grandmas are shown to wear different footwear overtime, Sarah was wearing a pair of brown boots just like the Mamas and Sisters during her service while Isabella wears a pair of black high heels and gray tights underneath.

Like the Mama and Sister positions, the grandma position is abolished as Grace Field House was raided, Peter Ratri's unexpected death, and the last grandma's betrayal.

Trivia

 * Isabella is the only known Grandmother who's eyes are visible.
 * Despite working for the Demons, the Grandmas have been shown to have some sort of control over certain demons - for example, commanding them to kill Sister Krone.
 * Grandma decides the names of the children born at Grace Field.