Appearance and Personality
XJ-1 is the youngest sister in the family, designed to be only one year old in mentality (despite being the first XJ-Sister created).
She is a simple machine shaped like an egg, with two short, small antenna-like features on her head, a clear top layer showing her lightbulb-like eyes, a mouth with one visible tooth, and a bottom layer resembling a diaper.
Being designed as a baby, XJ-1 is the smallest out of the XJs. She is cute, cry-babyish and happy. She was not programmed with the function to speak, but communicates with beeps and whistles (like the binary language), and cries like a baby. She gets startled and scared easily, and when she is frightened or upset, she will cry and leak oil from her eyes as tears.
Her only power is the ability to barf grease and oil. When her body is broken in two pieces, she releases a substance similar to a yolk. Due to her messy behavior (namely spewing or leaking oil) XJ-4 is constantly following her baby sister and cleaning up her messes.