The Dark Citizen
From Tardis Wiki, the free Doctor Who reference
The Dark Citizen was part of a universe where their race had conquered everything. They were originally a Time Lord.
The Dark Citizen helped the Eleven in his plans such as wiping out the Sontarans. They told him how they conquered the galaxy, and that they knew his future. They restored the most of the universe after consulting with the Seventh Doctor. (AUDIO: Dark Universe)