Trion (planet)

Trion was the home planet of the humanoid Trions. In 1984, Vislor Turlough, who had been exiled from Trion years ago, was allowed to return there. (DW: Planet of Fire)

At some point in its history, it was attacked by Tractators. (DW: Frontios)

The Tenth Doctor and Emily Winter visited Trion to make sure that Turlough didn't write the diary that the Advocate was using to manipulate Matthew Finnegan. (IDW: Final Sacrifice)