Mr. Nobody and Mr. No-one are spies of Mycroft Ward:

"There is a bit more to say on Mr Nobody and his associate Mr No-one. I think their histories both inside and outside of The Raw Shark Texts are pretty interesting. Also, they both have a pretty smart text-based/linguistic ability which is only vaguely hinted at in The Aquarium Fragment and in the main novel, but which makes them extremely efficient spies for Mycroft Ward. Nobody’s power and very strange nature were going to be spelled out a little more clearly but I decided it should be something for the very very obsessive reader and/or another time..."

The villain in Steven's Dr. Who audio story is called Nobody No-one.