Hellmouth is an ink illustration reimagining the medieval depiction of the gates of hell - a wide, gaping mouth hung tall, a pit leading sinners to the bowels of hell. The origins of this depiction stem from the Anglo Saxon "Vercelli Homilies", which describes Satan as a dragon that would swallow the dammed. It's described to never once close it's mouth, always remaining open for the flow of corrupted to fall through it.
I felt especially drawn to the idea of a mouth that could never close.
HellMouth is also associated with the Leviathan, the abomnible whale-creature-hell-gate-keeper whose open mouth emits a sweet smell to lure the easily tempted. Swallowing whole, like a snake, with food in its' belly that was once wholely something else.