A Hell Mouth Imp?

At the top of the steps, a 2ft tall demon imp flutters in the air, moving its bat-like wings faster than a humming bird in heat. Though, something seems to off with the demon imp, her mouth being twice as big as a normal one's and bearing burning cracks of low green fire that ru down her large lips. That's when the details start to click into place, and you recall a similar description for another beast. A Hell Mouth Imp.

Hell Mouths are a type of demonic creature with the ability to summon other demons and unholy creatures by creating a portal in their mouths. These demons are typically just smaller and weaker than others but are mostly used for either rituals, summonings, conquest, or just plain mischief. Although Hell Mouth Imps are the smallest, they can still summon demons of any kind and size and are seen as the most dangerous kind of demonic creature. Given their small size, those who do not know of them easily underestimate how effective they are as they can sneak or fly into any entrance as small as their head and can release an army of horrors on ignorant people in a matter of minutes.

Hell Mouths posses a small portal in their mouths' that sits at the very back of their throats. They can still talk, eat, and use their mouths regularly, but the portal becomes larger and smaller as their mouth opens wider and closes. They can also swallow mortals to send them to a personal pocket dimension within the Hell Mouth itself. These pockets can be anything between a new type of hell to a fictional heaven. Once the victim is inside, they will be slowly drained of their soul over tens of thousands of years to feed the tiny demon. Because the process is so slow, they often collect mortals whenever they are given a chance to increase how much they drain over time. If a hell mouth of any kind is killed, they will implode on themselves and permanently close off their connection to hell and seil off their pocket dimension, trapping anything within forever with no hope of ****, leaving their souls snared and bound to the plain permanently. They are often hunted and summoned to harvest parts such as teeth or tongues for special brews, even summoning rituals. However, this can be very problematic as they can, and will, summon a stronger demon or creature to protect them when they desire to, resulting in most mages and intellectuals making deals with them for the desired ingredients.

She is small with light blue skin and long dark black hair in clumps and dirty knots. A pint sized metal bra and thong covers her nudity but not very well. Her hands and feet are riddled with soot and stretched by short black claws. Her eyes and lips glow with a dark green burn of heat showing the power within her. A strange demonic symbol is branded on her upper right thigh, possibly to make rank or exile obvious. She floats down and lands on the top of the steps while resting her hands on her hips and retracting her wings. You would say you're surprised but you're past such unanticipated accurances at this point. Messy has hid in the pool, only letting her eyes and nose above the water as the rest of her is submerged and covered by the brown mist in the water. The Hell Mouth Imp doesn't seem to notice her as she walks down the steps toward you, clanking her sharp little claws against the wet stone. "Huh, another fool entering this damned chamber. Thought I snuffed out you loyals and all your churches. So... Who sent you?"

So she may be "guarding" this place but by her indications she's also hunting loyals of some church. You don't know what to say to her, but she wants an answer and she doesn't look like the type to wait long. She scowlles at you, impatiently.