Therefore, its known narrative elements are not a part of the Doctor Who universe as we, on this Wiki, choose to define it. It may have been the basis for a similar story in another medium, however — and that story may indeed be valid.
Requiem was an unproduced Doctor Who novel pitched by Lawrence Miles to BBC Books in late 1998 while writing Interference. It would have been the first in a miniseries of six connected books, published over two years in the BBC Past Doctor Adventures slots and featuring a future incarnation of the Doctor.
Requiem would have been set on a future version of Gallifrey, paranoid about the approaching War in Heaven. Suddenly, a "huge, black, bone-like thing" would have materialised over the Capitol and, rather than firing, sat there waiting. The future incarnation of the Doctor would arrive and discovered he was the only one who could get inside the object because it was "directly linked to his destiny" and the coming War. Over the course of the story, it would have been revealed that it was all a set-up by Faction Paradox following their damage to the Doctor's biodata in Interference.
Miles delivered an impromptu pitch for Requiem and its accompanying novels to editor Stephen Cole in the lobby of BBC Worldwide, but the concept was never seriously considered. Eight months later, Cole and co-author Peter Anghelides wrote The Ancestor Cell, which also featured a black bony structure hovering over Gallifrey in the lead-up to the War as part of a Faction Paradox conspiracy.
Stephen calls me up and starts haranguing me, saying things like "it's not remotely like your story, what are you talking about?" ... From what I can gather, what's on board the black boney thing in The Ancestor Cell is completely different to what was on board the black boney thing in Requiem, so I'd say there isn't enough similarity for a lawsuit or anything.