Milly (ミリー, Mirī) is one of the minor character of The Promised Neverland. She is a 1-year-old orphan who formerly resides in Grace Field House Plant 3 as one of the many foster children of Isabella. She only appears in the manga.
Milly was born at Grace Field in 2044 and sent to Plantation 3 a year later in 2045, growing up along with several other children under the parental care of Isabella. She sleeps in Isabella's room and was left behind with the younger children at Grace Field House, while the children over 5 years old made their escape. She is first shown in chapter 100. Along with Phil and other younger orphans like Carol, Eugene, Charlie, and Sherry, Milly now resides in at a different plantation at Grace Field under the care of Yukko after the Grace Field House Plant 3 was burnt down.
Milly most likely has average height, build and hair length for a girl her age. Like all the other children at the orphanage, she wears the standard white uniform, albeit the one for small children.
Milly is a happy, well-cared for girl, who loves her family.