Tersurus was a planet with singing stones and clone banks. (PROSE: All-Consuming Fire) It was mentioned as being in the "Outer Planets" in the Matrix. (AUDIO: Neverland)
History
In the Old Time, the Other sent Susan Foreman to Tersurus during the Great Schism so that she would be safe from the civil war erupting on Gallifrey. (PROSE: Lungbarrow)
May Zalrick bought Attow Eels on Tersurus. (AUDIO: The Havoc of Empires)
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. (PROSE: Legacy of the Daleks) According to another account, however, the Decayed Master attempted to attack a Time Lord outpost on the planet, and was left disfigured after a confrontation with a future incarnation, as part of a plan to join the Cult of the Heretic. (AUDIO: The Two Masters) In any event, a signal sent to Gallifrey by the Master's TARDIS drew Chancellor Goth to Tersurus, where he found the disfigured body of the Master. (TV: The Deadly Assassin)
The Time Lords had an outpost on Tersurus. The Master infiltrated this base on another occasion in order to gain forbidden knowledge on the Dimensioneers. (AUDIO: Dominion)
Missy recalled once climbing through the sewers on Tersurus. (AUDIO: The Bekdel Test)
After his TARDIS was damaged by a vortex parasite, the Eighth Doctor patched it up on Tersurus. (COMIC: A Life of Matter and Death)
In 6211, a Sontaran stealth raid destroyed Tersurus with an earthshock bomb which they had obtained from the Cybermen. (PROSE: The Crystal Bucephalus)
During the War in Heaven, the Memeovore consumed the Tersurans' forms of communication, so they had to evolve other, more tenuous forms. (PROSE: The Taking of Planet 5)
After the death of the Tersuran race, one version of the Ninth Doctor meets with a Master on Tersurus to tell him the news that he has plans to marry his companion Emma and retire.
The Master makes one final attempt to destroy the Doctor and his companion, Emma, by plunging them into the vast, labyrinthian sewers of Terserus. The sewers being so vast and complex, as well as disgusting and treacherous, it takes the Master himself 312 years to escape from them, being repeatedly knocked into the sewers on three separate occasions, requiring the Daleks to regress him back to a more youthful state. (TV: The Curse of Fatal Death)