"The Scarlet Moon is Kiva's herald"
This is the one fact known to all of Ponyville, the sleepy town haunted by a masked killer. Silent, except for the odd sound of a flute, summoning the Herald. And in the morning? Bodies. Crushed, full of holes, or slashed. All of them bearing the mark of Kiva. The victims? Good ponies, ones the town has known for years. The Guard's been organized to try and catch this masked killer, and Ponyville's own Elements of Harmony are after him as well.
Just one small catch. Fluttershy, the Element of Kindness is Kiva, and the good ponies she's killing? Fangires, stained glass monsters out for pony blood.
Everyone has a devil inside. The question is, does Fluttershy?
(Basic knowledge of Kamen Rider Kiva required.)