Here is a list of mythical creatures beginning with this letter and I am constantly gathering information from each continent and continually updating.
Aswang (Philippine)
Spanish colonists noted that the aswang was the most feared among the mythical creatures of the Philippines, even in the 16th century. Although with no specific motive other than harming others, their behavior can be interpreted as an inversion of the traditional Filipino's values. The aswang is especially popular in southern parts of Luzon, and some parts of Mindanao and Visayas, especially the Visayan province of Capiz.
The trickiest thing about an aswang is that it allegedly disguises itself as a human during the day. It goes about among humans and picks out its victims to hunt at night. Considered to be part vampire, part witch, and part “werebeast,” the idea that the Aswang could be walking among you without knowing it is one of the most scary things about it.