The Alliance (Fugitive of the Judoon)

The Alliance was an organisation that sought to prevent the return of the Cyberman Empire. In the 21st century, Captain Jack Harkness told Graham O'Brien, Yasmin Khan and Ryan Sinclair that the Alliance sent something back through time and space. (TV: Fugitive of the Judoon)

The Thirteenth Doctor and her friends later visited Mary Godwin, Percy Shelley, Lord Byron and Claire Clairmont in Villa Diodati in 1816 where they discovered that that something was some Cyberium and that a Lone Cyberman was searching for it in order to change the future. The Cyberman also recalled that his children had joined this "resistance" and so he had to slit their throats. (TV: The Haunting of Villa Diodati)

Ko Sharmus was a member of the Alliance, and later expressed remorse at sending the Cyberium somewhere where Ashad found it so easily. (TV: The Timeless Children)