Not long after the Wall of Despair discovered the army of Undead Creatures, they began to encroach upon and devour space little by little like a vast swath of night, like a dark world drawing ever closer.
Aside from those rotting, drifting Dementors, the sky's dark clouds had practically swallowed that entire stretch of heaven and earth. Even the thin wisps of cloud drifting through the air were black, like shrouds wrapping the dead in black mist. Any magical creature with the slightest understanding of magic, even if it was not a wizard, knew this was anything but normal.
From the outside, they resembled the sort of magic Dumbledore had loved casting in his youth, the Cloud-Mist Spell that could easily blanket an entire district in fog. The Undead's mist, however, was black. At the current distance, the wizards still could not determine whether it contained toxins, but gathered together on the far horizon, it looked like a black dividing line pressing gradually toward them. Wherever it passed, thick clouds completely blotted out the original sky, leaving not a trace visible.
If the wizards standing on the Wall used spells like the Eagle Eye Spell or telescopes, they could already make out the shapes of the Undead Creatures. But that was hardly a good thing, because every wizard who saw that sight could not help but draw in a sharp breath, a sound that filled those nearby who had not seen it with fear.
Those stark-white skeleton skulls, the Inferi with rolled-back white eyes, and the gray-faced Zombies were wrapped in the black mist. From time to time, twisted limbs, rotting palms, or hideous faces emerged from the black clouds, making this Black Tide look even more terrifying and disgusting than the intelligence they had gathered before—as if it were