The Accord

The Accord were a race of non-corporeal beings. They sought to fortify the timeline of the universe to prepare it for a series of "monstrous events" in their future. They feared that the 1970s and 1980s, which had been temporally weakened due to the Doctor's frequent visits, would be damaged and set out to reinforce the two decades before they were hit by the war. They altered the DNA of every single person that lived through those decades on a temporal level so that they subconsciously realised that there were inconsistencies with history. (PROSE: The Enfolded Time)

The Doctor created the Laughing Gnome as an interface for them to interact with Alistair Gordon Lethbridge-Stewart and send his astral body through time. (PROSE: Lucy Wilson and the Bledoe Cadets)