Cryon

Cryons are a humanoid race from Telos.

Biology
Cryons are pale and lean, with long fingers, enlarged craniums and whitish skin. They also have slow movements and echoing voices. Due to their unusual composition, they can't survive above sub-zero temperatures and will steam and boil if they are subjected to heat. (DW: Attack of the Cybermen)

Technology
The Cryons have reasonably advanced technology, but they especially excel in refrigeration technology. This advanced refridgeration technology is what brought the Cybermen to Telos. They were also able to contact Earth from Telos. (DW: Attack of the Cybermen)

History
The Cryons lived in peace until they came to the attention of the Cybermen. The Cybermen came to Telos and took over the refrigeration to use for suspended animation. They also attempted to wipe out the Cryons, but some survived and were able to contact Lytton in order to hire him. (DW: Attack of the Cybermen)