The Brotherhood take Arya to their hideout in vast underground caverns lined with weirwood roots.
This one was fun to do. Though the roots were a pain to shade.
In my personal head cannon, the weirwoods are even more alien than we suspect. To the point that they might not even be plants. It’s always fun to show this.
A huge firepit had been dug in the center of the earthen floor, and its flames rose swirling and crackling toward the smoke-stained ceiling. The walls were equal parts stone and soil, with huge white roots twisting through them like a thousand slow pale snakes. People were emerging from between those roots as she watched; edging out from the shadows for a look at the captives, stepping from the mouths of pitch-black tunnels, popping out of crannies and crevices on all sides. In one place on the far side of the fire, the roots formed a kind of stairway up to a hollow in the earth where a man sat almost lost in the tangle of weirwood. Arya VI – pg 460
