A subterranean tempest fire creature with a slender body and long spikes on its back. The Knucker has short muscular legs and a forked tail. It is surrounded by a large cloud of dark grey smoke with an eerie glow, as if lit by the embers of a thousand burning fires. In the sky above, two white umbra wings stretch out from behind the creature, their edges translucent and ethereal, casting no shadow on the ground below as they beat steadily to keep the Knucker aloft in this turbulent atmosphere.