An ex-courier, Driven by something he doesn't understand
Nathanial is the courier you met in the Government District, building an invisible wall outside the Architect’s Temple of Bemel.
According to Andrea, The Builder’s assitant, he was building something with the bricks of a building that should have fallen during the earthquake, but did not. Although no one else could see or touch the blocks, they seemed real enough to Nathanial, who split his hands open with the unfamiliar work of masonry.
The wall later stopped one of the Astral Spiders from entering the city, creating a strange and horrifying sight of it hanging half in half out of reality, high bottomed on the wall Nathanial had nearly finished.
The party intervened on his behalf with the Watch and, with a little help from Lady C, convinced them that Nathanial was in fact a hero, not a criminal to be arrested.
Nathanial was dead, apparently killed by Cinnamon during some sort of fugue state while she slept. He has been returned to life by the Necromancers, and appears to hold no grudge. He spoke of Cinnamon cutting her way into reality from ‘elsewhere’, which the more magically-inclined members of the party suspect was made possible by Lady C’s pocket dimension, which allowed Cinnamon’s Astral parasite to exert control it normally would not be able to.
Finally, Ivraham has indicated that Nathanial is the first of a new group of protectors of the city, better suited to protect the city from the troubles from ‘elsewhere’.