Miri

Miri was born on the Earth-like planet, Juram V, in 1955. Due to a life-prolongation experiment being conducted on the planet around the time of her birth, all the children on the planet had greatly increased life-spans, while all of the adults perished.

When the USS Enterprise arrived in orbit of Juram V in 2266, Miri was over 300 years old. When the landing party encountered Miri she was very frightened of the grups, but later developed a liking to the humans and an attraction to Captain James T. Kirk. Because of Miri's position of respect for caring for the younger "onlies" on the planet, she was able to convince the children to trust the Enterprise landing party and allow them to develop a cure for the life-prolongation drugs that were killing them. (TOS episode: "Miri").

When the Enterprise left Juram V, they left behind a team of experts to educate the "onlies" and help them to assimilate to a new way of life, with Miri's support and guidance. However, the cure for the life-prolongation didn't work on the children as well as on adults, and Miri died a few years later after she reached puberty. (TOS novel: The Cry of the Onlies).