Over a dozen faceless robed war mages riding steam-hissing clockwork animals, whose dispel strips Carl's smoke and the tunnel roof.
Through the haze Carl first mistakes them for mages on horses, then realizes the mounts are not real: a menagerie of Clockwork Mounts including horse-like creatures, a dinosaur resembling Mongo, a horse-sized cat sleek as a panther, and an insect terrifyingly similar to a mantid hunter. The mounts whir, click, and hiss steam as they advance past the stalled The Bone Clan troopers.
The riders wear glowing, flowing robes with their faces obscured, too distant to get a description, and there are over a dozen of them — enough to fill Carl with a primal sense of foreboding. One of them casts a Dispel powerful enough to erase all of Carl's smoke and cancel the Dwarven Digger Tunnel's roof fortifications at once, dropping the whole party underground. Several war mages fall in with them; the Semeru Dwarves shout "War mage in the tunnel!" and "Not so tough with the magic turned off," then hunt them down in the dark.
Over a dozen riders in glowing, flowing robes with faces entirely obscured, mounted on whirring, steam-hissing clockwork beasts.
They are the elite enemy caster corps whose overpowering dispel accidentally drops Carl's party to safety.