Rini is one of the central characters in the Sailor Moon series. She is the daughter of Serena and Darien from the future. She has the Luna Ball
She is also a Sailor Scout, Sailor Mini Moon. When she first appears, she is a small child from the 30th century who visits the past to seek help from the series' primary heroines, the Sailor Scouts. She later returns, a few years older, in order to train as a Scout herself—Sailor Mini Moon.
But in the dub during the 20th century she goes by the name Rini Tsukino. She is given her nickname by Darien Shields in the manga and Serena in the anime in order to differentiate from the older Serena Tsukino, Sailor Moon. The nickname is a diminutive of her given name, Serena. In her own time period, she is always called Little Lady (or Small Lady).
Rini does not transform into Sailor Mini Moon in the first movie, but she does in the other two. However, in the third, in which she is the deuteragonist, she is among the children who are taken onto Poupelin's gondola for the wicked Queen Badiane.