By Alan McCoy from Dungeons & Dragons: Fundamentals
How to build challenging
encounters against a Harpy
Note: This has been prepared utilizing only the 5E Core Rules. The Harpy can be found in the Monster Manual page 181.
Note that this is one of the monsters that I feel the Monster Manual has gotten wrong, probably because they needed more CR 1 monsters and doing it correctly would have pushed it far out of that bracket. This is one of the classic monsters of mythology, it deserves better treatment. I will be giving my own twists upon it following the official information.
The harpy is a foul tempered flying predator with a divine voice. It is not a natural creature; it is the product of a divine curse. The nature of this curse makes them hate. While generally they hate anyone not afflicted by their curse, the specifically hate handsome men and will choose them as victims above others.
The harpy combines the body, legs and head of a female human with the wings and wicked talons of a formidable bird of prey.
Step 1) Let’s review what we know about the Harpy.
The Harpy looks like an attractive female with bird wings. It has arms but instead of hands has wicked grasping talons. It can hold and wield a club.
Harpies are female. (NOT RAW — Harpies mate with handsome males to produce progeny.)
Harpies are cowardly.
The Harpy can fly 40 feet or walk 20 feet per round.
The Harpy is above average in Strength, Dexterity, Constitution and Charisma; has Average Wisdom, and Below Average Intelligence.
Despite being monstrosities, and their low intelligence, Harpies can Speak the Common Tongue and have real cunning when it comes to their hunt, they are not very adaptable however, once their attack has been disrupted, they are far more likely to retreat than to continue. Harpies are rarely encountered in groups of less than three.
Harpies can produce a beautiful song which lures all that hear it to come closer.
Step 2) Determine the probable Strategy.
The core of the Harpy strategy is to use their voice to lure victim into a situation from which it will suffer serious injury or death, then finish off their weakened opponent or feed on the remains. Harpies are scavenger-carnivores and have no problem with eating the leavings from the kills of other predators.
Step 3) Determine Tactics
Let’s start with Location: Harpies nest and hunt near some natural hazard that can be fatal to those who lack the ability to fly. Examples include Cliffs, Quicksand, Pitfalls, Bogs, or onto the territory of an aggressive predator or defender. Preferably one that’s a sloppy eater.
Assuming an appropriate hunting ground, the Harpy will begin it’s lure by singing a few notes of its song to draw the attention of the prospective target. This can be heard 300 feet away, but distance so dilutes the effect, the harpy won’t put any real magic into it until the prey is far closer.
The harpy will roost, hidden by cover, above the natural hazard or monster that it has chosen. Occasionally singing a snatch of her song until the prey is within thirty feet. It will then utilize its song to incapacitate the prey, either drawing them into the hazard or rendering them helpless as they are attacked. Almost always this natural hazard can be considered difficult terrain at best.
It will then fly down to finish off the injured or incapacitated foe, with its multi-attack of claw and club.
If it cannot kill a target within two rounds, it will disengage and fly, Dashing away at 60 feet/round.
MY TAKE:
While I like the idea of the Harpy being able to pick up a club and wield it, the normal multi-attack should be two claws. The club would be reserved for a harpy during mating season, to subdue.
The DC of the Wisdom Saving throw is far too low at DC 11, even the unluckiest average human will almost certainly break free in the 300-foot journey to the Harpy. I would raise this DC 13.
The immunity granted to a particular Harpies Song of 24-hour duration following a successful Saving throw is far too powerful. I’d give it an hour.
A group of harpies who sing together are called a Siren, and their song is even more powerful. The pull of their combined song raising the DC of the Saving Throw by ONE for every harpy in the group. (2 harpies = DC 14, Three = DC 15, Four = DC 16 etc.