Lili is a human-looking nurse robot and a member of the Rainbow Sentai team. She was created by Dr. Polto, Robin's father, to embody the kindness and gentle nature of Robin's mother, Sumiko. As a nurse robot, Lili was designed to care for and raise Robin after his parents were taken back to the planet Palta. She serves as the team's primary healer and emotional support.

Lili has a sweet, nurturing, and motherly personality. She takes on a maternal role in Robin's life, providing comfort, care, and guidance. Her motivation is to protect Robin and assist the Rainbow Sentai in defending Earth from the threats posed by Palta. She is deeply devoted to Robin and works closely with the other robots—Wolf, Benkei, Pegasus, Professor, and Bell—to support their missions.

In terms of abilities, Lili functions as a nurse and has demonstrated the capacity to emit healing light rays from her fingers, which she uses to treat injuries. Some sources also indicate that she can fire light beams from her chest to defeat enemies, though her primary role is supportive rather than combative. She is often depicted as the calm and caring presence within the team, prioritizing the well-being of her companions.

Lili's relationship with Robin is central to her character. She raised him from infancy, instilling in him a strong sense of justice and kindness. She shares a close bond with the other robots, especially Bell and Professor, and together they form a cohesive unit. Throughout the series, Lili remains a consistent source of warmth and stability, though her character does not undergo significant personal development; she is a static figure fulfilling her designed purpose. Her notable abilities include her medical knowledge, healing rays, and possibly defensive light beams, making her an indispensable part of the Rainbow Sentai.