At one time Cryons, who died instantly when exposed to temperatures above zero degrees, lived on Telos. The Cryons moved under the surface when it became too warm, constructing underground cities refrigerated to the zero temperatures the Cryons need to survive. The Cybermen later came to steal the refrigerated cities to use as repositories of Cybermen cryogenically frozen in suspended animation. The Cybermen killed most of the Cryons. (DW: Attack of the Cybermen) The Cybermen from Lonsis were twice destroyed by the Eighth Doctor. It seems after Mondas was destroyed the Cybermen moved to Lonsis, planning to invade Earth, foiled by Charley Pollard who infected their ship with temporal corrison, and later the Doctor who increased the range of a Quantum Crystalliser programmed to destroy them. The few survivors of these attacks colonised Telos, while Cybermen from other parts of the Universe colonised other planets.
- This was not the only planet on which the Cybermen left reserve armies, awaiting revival.
Five hundred years after the last known encounter between Humanity and the Cybermen, an archaeological expedition from Earth, led by Kaftan and Eric Klieg of the Brotherhood of Logicians landed on the planet to find the Cybermen and to revive them. With the Cybermen as their army, they planned to impose a regime of pure logic on Human society. The Cybermen were resurrected, and also their leader, the Cyber-Controller. The Doctor was able to seal them back inside their "tombs" and to electrify the outside gates. (DW: The Tomb of the Cybermen)
The Cyber-Controller was not, as the Doctor had believed killed, but survived, and had installed a base, known as Cyber-Control underground, supervising operations on 1985 London, with which they had a communications link and fighting the Cryon rebels who remained. The Cybermen at this time employed work parties of Humans whose conversions were unsuccessful as slaves to mine the surface of the planet. The Cybermen intended to destroy Telos and to observe its blast pattern for future research. The base was, however, invaded and destroyed by the Doctor (now in his sixth incarnation). (DW: Attack of the Cybermen)
After the Hotel Historia on Earth was invaded by Graxnix, manager Majenta Pryce decided to flee and relocate to somewhere like Telos, claiming that it could use a little remodeling. (DWM: Hotel Historia)