A druidic order integrated into The City since before it left The Old Lands.
The Order of the Lightning Keepers is a druidic order from The Old Lands, having integrated into The City long before the appearance of The Nightmare. Though back then they were simply known as the Rooftop Order.
They are the originators of the city tradition of roof-top gardens and bird roosts, and still maintain many bird roosts themselves. However, these days they are more known for their command of lightning, which they can direct from the top of the pylons surrounding The City and fragments, when The City is attacked directly by outside forces.