Luminite

Luminite is a luminous substance found underneath the City of Lights. It is an extremely energy dense material and is used within the city as a source of power and light. It has enabled the City of Lights to create their railway system, create large searchlights on top of the Walls to deter nephilim, create street lamps that light up the city, etc.

Engineering
The discovery of luminite has also created a new type of work for humanity. It has started an industrial age within the City of Lights and many commodities are starting to be mass produced. It has now taken its place as one of the three pillars of the City of Lights, together with magic and alchemy.

There are two organizations that focus on luminite engineering: the Luminite Research Foundation, which focuses on innovating with the use of luminite; and the Ironworks Industrial Union, which focuses on the managing of the industries using luminite.