Rhodia

Rhodia was a planet, according to Charlie, "more beautiful than you could ever believe", "paradise". A planet of three billion, it was home to two dominant species: the Rhodians and the Quill. (TV: For Tonight We Might Die)

Landscape
Red leaves seemed to be everywhere. The Quill inhabited the smallest of the southern continents. (TV: For Tonight We Might Die)

History
According to Miss Quill, the Rhodians ate up all the planet's resources, including that of the Quill. They tried to help the Quill, but in the process made them so dependent that they could never recover.

The two species were eventually at war with each other. The Rhodians won, enslaving the Quill with arns.

While they were busy fighting amongst themselves, the Shadow Kin arrived, and killed everyone, all three billion, Rhodian and Quill alike. The only two survivors of Rhodia were Charlie and Miss Quill, the last of their respective species, who were rescued by the Twelfth Doctor, and brought to Coal Hill Academy in 2016. (TV: For Tonight We Might Die)