Global Link is a method used by Sanctuaries around the world to communicate with each other instantly. The only known way to communicate through it is by sending videos.
The Supreme Council used it to communicate with other Sanctuaries, including the Irish Sanctuary. Bernard Sult was murdered live on the Global Link to initiate the war on Ireland. It is also used in the same war by Skulduggery Pleasant to stream the footage of Ghastly Bespoke and Anton Shudder being murdered by Ravel, Cleavers and the Children of the Spider.