Only enough flesh to keep Lith's memory and mind intact remained, everything else was an ever-shifting mass of pure darkness, so thin that it was nigh-two dimensional.
It was the Shadow Step bloodline ability that belonged to Dark Phoenixes like Kigan and Raaz, were Lith's father ever to Awaken his dormant abilities. The Demons followed suit, disappearing from sight and slithering along the corners of the streets to go unnoticed while they spread throughout the city.
The Voidfeather Dragon's mass was much greater and something of his size moving around was hard to miss, no matter how thin he made himself. He split his body into smaller pieces moving small groups of them at a time but always keeping the fragments close enough to not lose control over them.
This way, he could hide in plain sight, even using bystanders and carriages to move around more quickly.