Secret Architect
From Tardis Wiki, the free Doctor Who reference
The Secret Architects were the creators of the City of the Saved.
Some believed that the City was Heaven and it was made by a god or gods. Others thought it was a pocket universe made by advanced humans. Speculation that it was a far-future version of Mictlan was popular. Compassion's involvement was suspected as well. (PROSE: The Book of the War)
The last was the most accurate. The City was Compassion, or at least her interior dimensions. She created the environment, and then was helped by the Universal Machine to perform the resurrections of all humanity. (PROSE: Of the City of the Saved...)
