The why of the beast in the woods

The beast in the woods is a trope I'm fond of. The town is haunted by a beast that kills man and livestock indiscriminately. It lurks in the woods during the day and only emerges when it can cause the most fear — during night or thick fog. Swords don't hurt it, arrows seem to pass harmlessly through it. Worse yet, if you somehow do kill it, it comes back. Because the beast is just a manifestation of the curse afflicting the town. A curse one or more of them brought down on the whole community by committing a crime so vile that the gods turn their faces away and nature itself rebels.

The only way to dismiss it for good is to reveal the crime and punish the transgressors.

The beast is a huge 

1. shadowy
2. skeletal
3. smoking
4. bloody-coated
5. grave-smelling
6. glowing

1. stag
2. ram
3. boar
4. wolf
5. bull
6. chimera

with

1. human qualities.
2. burning eyes.
3. a crown of flames.
4. dripping poison.
5. iron fangs.
6. twisted horns.

You know it's near when 

1. a fog rolls in.
2. a frost forms.
3. a storm begins.
4. a cloud of locusts forms.
5. animals panic.
6. dogs howl and babies cry.

It brings

1. pestilence
2. madness
3. ghosts
4. insidious whispers
5. a flock of enraged crows
6. souring and rot

and

1. the sound of women lamenting.
2. blight to crops.
3. disturbing shapes in torch and hearth flames.
4. the buzzing of flies.
5. causes lights to darken.
6. rumbling in the earth.

Worse yet,

1. metal weapons strike sparks from it.
2. it leaves burning paw/hoof prints.
3. the earth turns barren where it walks.
4. chains shatter on it.
5. holy symbols grow hot in its presence.
6. corpses twist and contort when it's near.

It's here because

1. someone starved a dependent elder.
2. a parent abandoned a child to die.
3. a host broke the laws of hospitality and murdered a guest, or vice versa.
4. someone broke a sacred vow and won't make amends.
5. a believer defiled a holy place.
6. someone completed a deal with a ruinous power.

(Thanks to Spwack of the Slight Adjustments blog for the generator code.)