Mordee

An Earth-like planet had at least part of its surface covered in dense jungle. The Horda was one of the native life forms.

In the far future, the planet was colonised by the Mordee expedition. Shortly after they arrived, the Fourth Doctor visited and assisted them in repairing their computer, Xoanon. Centuries after his original visit, the Doctor returned to the planet, only to find that the Mordee had split into two groups, the Sevateem and the Tesh, both of whom worshipped Xoanon, who had gone mad from the Doctor's efforts to help. After restoring Xoanon's sanity and reuniting the two tribes, the Doctor left, accompanied by the Sevateem warrior Leela. (TV: The Face of Evil)