The Severed Union was very secretive, and quite obviously extremely effective in their ability to hide their traces. The ones that mattered, at least.
The imposition of what was called a Union Seal, had allowed the organisation to keep its existence a secret even from Arch-Mages and Diviners.
Union Seals were inconspicuous brands that anyone who ever set foot in the Severed Union had planted on their bodies.
The main purpose of the Seal was to lock all memory, and immediate thoughts about the Severed Union from intruding egos.
Replicus had found it ingenious that unlike most constructs of similar nature – restrictive binds that acted on live targets – what made the Union Seal effective was the fact that it left room for implications about the Severed Union, but barred all specifics.