Welcome the the 2015 A to Z blogging challenge.
This year I am going to take on Vampires. Talk some history and present some stats for various games. It should be fun.
So it's April 1st. Lets get started.
The Aswang is a shapeshifter. It can appear as a normal townsperson, an animal like a dog, cat or pig or as a horrible monster like a ghoul or werewolf. The creature can move about during the day in it’s “human” form but can’t use any of it’s special attacks.
Also the subject of a 1994 horror movie, http://en.wikipedia.org/wiki/Aswang_(1994_film) and an episode of Grimm.
Armor Class: 2 
Hit Dice: 6d8+2** (34 hp)
No. of Attacks: 2 claws, 1 bite (monster form) OR 1 (human form)
Damage: 1d6+2 / 1d8+1 OR by weapon type.
Special: Blood drain, cause fear (as per spell)
Movement: 30’ 90' fly
No. Appearing: 1 (3-9 in nest)
Saves As: Fighter 6
Alignment: Chaotic (Chaotic Evil)
The Aswang can cause fear as per the wizard spell up to 3 times per day. It can also shapeshift into dogs, cats or pigs like any other vampire can turn into wolves or bats. An aswang can not become mist, but can grow large bat like wings and fly away.
The bite of an aswang drains blood. An successful combat roll of 19 or 20 while biting means the aswang has locked onto the victim. The aswang will then drain 1 point of Constitutions worth of blood each round. The aswang will typically feed for 1d4 rounds and then try to flee. Anyone brought to 0 points of Constitution will die and rise an aswang on the next full moon.
A holy symbol will keep an aswang away like a normal vampire. As will garlic and a line of salt.
It is rumored that the only way to capture an aswang is to use a whip made from a stingray's tail. Once captured the aswang can not use their magical abilities. The only way to defeat the creature is to cut off it's head.
The creature can only be hit by magical weapons, but a weapon coated with oils prepared by a village priest (an albularyos) will also be effective.