Hag

A hag is a savage being that looks like an ugly, old witch but has more warts, they are not human nor former humans. They possess rudimentary magic, similar to that of a troll. Little is known of them, though it is thought that they are what Muggles think are witches and are therefore popular in Muggle literature.

Hags are not pleasant to be around. They are nasty, malevolent, and haggardly.

Compiled partially from Hag at the Harry Potter Wiki.

Hag Magic

Hags cannot use wands. They rather specialize in earth magic. They are especially apt in potionsmaking and herbology, but tend toward the darker side of the spectrum. This magic seems to be different from that found in normal witch cabinets.

Hags can shapeshift between two forms, between being a beautiful woman and a foul looking wretch. The foul and hideous wretch is their primary form and it is the form they must take most of the time.

Diet

Hags eat children and raw liver are part of their diets.

Habitats

Hags can occasionally be encountered in Diagon and Knockturn Alleys, as well as Hogsmeade; however, some hags live in caves.

Ministry classification

The Ministry of Magic classifies hags as beings, a fact that causes centaurs and merpeople to desire the classification of beast.

Relations

As hags are rather unpleasant, witch/wizard relations with them are very rare. It is not possible to breed with a hag, but the insult to suggest that someone's mother was one, is to imply that someone is very ugly. The criminally desperate might be tempted to engage a hag for brief release, though this is not particularly pleasurable for either party and socially frowned upon.