Green Hag

(from 5th Edition Monster Manual - 2014):

The wretched and hateful green hags dwell in dying forests, lonely swamps, and misty moors, making their homes in caves. Green hags love to manipulate other creatures into doing their bidding, masking their intentions behind layers of deception. They lure victims to them by mimicking voices calling out for help, or drive unwanted visitors away by imitating the cries of fierce beasts.

Obsession with Tragedy. Green hags revel in the failings and tragedies of other creatures. They derive joy from bringing people low and seeing hope turn into despair, not just for individuals but also for whole nations.

When hags must work together, they form covens, in spite of their selfish natures. A coven is made up of hags of any type, all of whom are equals within the group. However, each of the hags continues to desire more personal power.

A coven consists of three hags so that any arguments between two hags can be settled by the third. If more than three hags ever come together, as might happen if two covens come into conflict, the result is usually chaos.

(from 5th Edition Volo's Guide to Monsters - 2016):

HAG LAIR ACTIONS:

If a hag is a grandmother, she gains a set of lair actions appropriate to her nature, knowledge; and history. A coven that includes a grandmother can use her lair actions as well, but the grandmother's will prevails-if one of the coven attempts this sort of action and the grandmother disapproves, nothing happens. A powerful auntie (or her coven) might also have access to lair actions like these, but only at certain times of the year or when the influence of the Feywild is strong. The following lair actions are options for grandmothers and powerful aunties. Grandmothers usually have three to five lair actions, aunties usually only one (if they have any at all). Unless otherwise noted, any lair action that requires a creature to make a saving throw uses the save DC of the hag's most powerful ability. 

Lair Actions On initiative count 20 (losing initiative ties), the hag can take a lair action to cause one of the following effects, but can't use the same effect two rounds in a row: 

• Until initiative count 20 on the next round, the hag can pass through solid walls, doors, ceilings, and floors as if the surfaces weren't there.

• The hag targets any number of doors and windows that she can see, causing each one to either open or close as she wishes. Closed doors can be magically locked (requiring a successful DC 20 Strength check to force open) until she chooses to make them unlocked, or until she uses this lair action again to open them.

Green Hags:

Green hags inhabit dismal forests, swamps, and moors. A green hag's body, whether broad, narrow, fat, or thin, is topped with a tangled mane of hair. A green hag thrives on creating despair and tragedy in the lives of her victims, using her skill with illusion magic to help in this goal. Destroying the hopes of others brings her unbridled joy.

A powerful green hag might have the following additional lair action: 

• The hag creates an illusory duplicate of herself, which appears in its own space. As long as she can see her duplicate, the hag can move it a distance equal to her walking speed as well as make the illusion speak on her turn (no action required). The illusion has the same statistics as the hag but can't take actions or reactions. It can interact with its environment and even pick up and hold real objects. The illusion seems real in every way but disappears if it takes any amount of damage. Otherwise, it lasts until the hag dismisses it (no action required) or can no longer see it. If the hag uses this lair action to create a new duplicate, the previous one vanishes, dropping any real objects in its possession.

(from 2nd Edition Monstrous Manual - 1993):

These wretched creatures live in desolate countryside and amid dense forests and swamps. Greenhags, as their name implies, have a sickly green pallor. Hair color ranges from near black to olive green, and their eyes are amber or orange. Their skin appears withered but is hard and rough like the bark of a tree. Due to their coloration and their ability to move with absolute silence, greenhags impose a -5 penalty to an opponent’s surprise roll when in a forest or swamp. They have superior hearing, smell, and sight, including infravision (90-foot range). They are only surprised on a roll of 1 on the 1d10 surprise roll.

Rock-hard talons grow from the long, slender fingers of greenhags. They use these talons to slash and rend their opponents. Smaller than their annis cousins, greenhags nonetheless possess Strength equivalent to that of an ogre (18/00). Because of their great Strength, all their attack rolls gain a +3 bonus and all hits receive a +6 damage bonus.

Greenhags can cast the following spells at will, one spell per round: audible glamor, dancing lights, invisibility, pass without trace, change self, speak with monsters, water breathing, and weakness. Each spell is employed at 9th level of ability.

To lure victims, greenhags typically use their mimic ability. This enables them to imitate the voice of a mature or immature male or female, human or demihuman. Calls for help and crying are common deceptions employed by greenhags. They are also able to mimic most animals.

Greenhags speak their own language (a dialect of annis) as well as all demihuman languages and common. These are the longest lived of all hags — they can live for up to 1,000 years.