Whisper Man

 were a group of featureless beings that appeared to serve the Great Intelligence. They kidnapped the Paternoster Gang, Strax, Vastra and Jenny Flint, forcing the Doctor to travel to Trenzalore and face his fate.

Appearance, Biology and Abilities
The biology of the Whisper Men is unknown. They could morph into the appearance of Walter Simeon at will, and much like the human embodiment of the Great Intelligence, seemed to be hollow on the inside, or unreal. When struck by Strax, one simply appeared to evaporate where hit, and then reform. They could also pass their limbs through flesh, when instructed by the Great Intelligence to stop the hearts of the Doctor's friends. They moved slowly, and lacked features, with blackened skin around their mouths and sharp teeth. They had angular faces with vague depressions where eyes should be, and exaggerated chins and cheeks. They wore the same Victorian garb as the Great Intelligence's form as Walter Simeon. It was stated that they could kill with a whisper, and they spoke in rhyming couplets, although their mouths did not move in time with what was being said. They appeared to hiss at their victims, and travelled in small groups when attacking. (TV: The Name of the Doctor).

History
Little is known about the Whisper Men. However, it is possible that they are representations of the scattered form of the Great Intelligence due to their ability to morph back into the appearance of Walter Simeon when one copy of him is destroyed. Their name is derived from their ability to kill with a whisper, and the whispering that accompanied their presence. (TV: The Name of the Doctor).

Behind the Scenes

 * The Whisper Men may have been made as an in-universe joke of the Silence, seeing as they Whisper instead of being Silent. The Silence also tried to stop The Doctor saying his name, whilst The Whisper Men tried to make him say it, with The Great Intelligence's orders.