Tersurus

Tersurus was a planet that had singing stones and clone banks. (NA: All-Consuming Fire) Following a ploy with the Daleks on 22nd century Earth the Master travelled with Susan Foreman in his TARDIS to Tersurus where she believed she killed him. During the encounter his TARDIS sent a signal to Gallifrey that brought Chancellor Goth to Tersurus who then found The Master. (EDA: Legacy of the Daleks, DW: The Deadly Assassin)

Behind the Scenes
In the spoof The Curse of Fatal Death Tersurus was the location that the Ninth Doctor met the Master on. According to both the Master and the Doctor, the Tersurons were the most gentle though shunned race in the universe. They communicated through carefully controlled "gastric emissions", and became extinct when they discovered fire. They were referred to as 'The nicest race in the universe, yet simultaneously the most hated and shunned' for this very reason.