B is for...

Banderhobb
Basilisk
Bear
Beholder
Black Pudding
Blink Dog
Brownie
Bugbear
...


Banshee.  Down a street, in a dark alley, over the hill, from deep in the forests, from across a still, black lake, you hear a woman sobbing, wailing uncontrollably.  Her sorrow cuts her to the bone, and chills you to your core.  You don't want to hear her, you don't want to see her; she's not behaving appropriately.

But your callousness is your downfall, and it's too late for you.  The banshee cries uncontrollably over a death, but whose?  Is she crying for her last victim?  Does she cry for you?  Or does she cry for someone else entirely, and you're just collateral damage, your life force leeched from your body by the empty black of her grief?

Some say the Banshee was a poor woman, mourning the death of a child, a lover, a friend.  Alone in the world, her grief ignored by all, her sorrow grew unbearable.  Slowly it consumed her, and she remained in mourning even to her death.  But her sorrow was hungrier even than death, and she remains, wailing, grieving until the end of time, lashing out now at those who would ignore her sorrow.

A serpentine lower body, the upper body and face of a once beautiful woman, now decayed.  The banshee sits beside watery places, washing the blood out of someone's shirt.  You may be traveling with another, but your companion won't hear; when the banshee calls, she calls for you alone.  Your death is assured, and you are the only one who knows.