We're gonna play all day today!
A single young Maenad is found on one of the lowest floors in the Depths of the True Moon who responds to Rydia and says she awaits her commands, much to Rydia's confusion. Rydia asks the Maenad to wait for her and after the final battle, the Creator chases the party through the bottom level of the True Moon, and the other Maenads defend the party from him.
The party reunite with the single Maenad waiting for Rydia. The Maenads tell them to watch over the child, as she is what remains of them. They defeat the Creator with the Meteor spell and the party escapes with the Maenad to the Lunar Whale, and returns to Earth.
In Mist, the Maenad starts a new life. Rydia names her Cuore, and trains her as a summoner, though she has trouble breaking the habit of talking like the other Maenads. Leviathan and Asura remark how Cuore resembles Rydia when she was a child. Rydia introduces Cuore to them as her parents and when Edge arrives, much to Cuore's excitement, she asks him to play with her, and promises Edge she will not use any magic.
Cuore is the Italian word for "heart", in the sense of the cardiac muscle as well as a person's inner mind. In The After Years, this might reference what the Maenads said about Cuore being what remains of them.