Night Howler (5e Creature)
From D&D Wiki
Small monstrosity, unaligned
Skills Stealth +6
Dark Stalkers. The night howler magically emits an aura that prevents creatures with darkvision from seeing in darkness within 120 feet of it while the night howler is in dim light or darkness. Any creature affected can still see in bright light and dim light as if they were a human. An effect that cancels magical effects prevents this from happening. Additionally, The night howler cannot have its speed reduced if it is in total darkness, and loses any reduction to its speed if it enters total darkness.
New Moon Hunters. The night howler has advantage on attack rolls against a creature if both the creature and the night howler are in total darkness. Dim or bright light, including that of the full moon, prevents this advantage.
Fire Catchers. The night howler is instantly destroyed by fire. However, any night howler struck by fire damage instantly damages the fire as if they succeeded on a bite attack on it. If this would snuff out the fire, the night howler is not instantly destroyed, but still takes damage. If the night howler dies this way, it disintegrates in a magical explosion of dust and ash which is otherwise harmless to others.
Gone By Day. The night howler is forced into the Ethereal Plane when hit by sunlight, and can return as an action when in dim light or darkness. It cannot willingly enter the Ethereal Plane from this ability.
Night howlers attack in swarms, but never kill creatures they hunt except for specific, single targets. They feed off of fear and unease, and need no other sustenance. Night howlers are often put to use by religious cults and even some established churches, used to hunt down traitors that have crossed the line, but only to those that used to be members of such groups. Night howlers given a single scent can hunt down that one person as long as they are on the same plane of existence. They strike from the shadows, going for every light source in the area first to the exclusion of everything else, including their targets. Should they snuff out the lights, their naturally magical aura means even the keenest sight is near worthless against them.
Night howlers used to be normal wolves. Something happened that no one ever documented that brought these nightmares to life, but they have a passing resemblance to their larger cousins that gives it away in spite of their dark purple, blue, and occasionally black fur (and often times mixes of the three). Because of the night howlers special diets of emotion, they usually only attack if absolutely necessary to survive, and prefer to use their slightly menacing glowing gaze to put people off without actually becoming harmful to them. However, even as word spread about this harmless phenomenon, people caught the idea to weaponize it, taming the creatures as animals and teaching them to hunt. This new danger put people back into a state of unease when seeing things stare back from the dark, and because of that, the interference actually ended up benefiting the entire species as a whole.