At firdt, Harpies are very much like human girls, but with bird characteristics. They are human from their head to their waist, but have feathered thighs and falcon legs with sharp talons. They also have a pair of wings that permit them to fly. They will most often wear tops or dresses, but nothing that would cover their legs.
Later on, Harpies have a more accentuated look. They are entirely purple from head to toe. Their hair is shaped like a two-horned crest on top of their head and their eyes glow a bright pink-purple color. Most will wear a jumpsuit-like attire with a leather belt. Their forearms are covered in feathers and their hands are clawed with talons. Their thighs are also heavily feathered and their feet are those of a hawk or falcon. They have a huge pair of wings and a long tail that ends with a little palm-like formation of feathers. The only one seen in the series also had a pouch attached around its waist to store personal objects.
From what is shown in the series, Harpies do not seem to actually possess magical powers. They are, however, very able fighters. When they've spotted their prey, they will lunge at it from the sky and attempt to slash it with their talons. Their claws are sharp and strong enough to cut through Dragon scales. When confronted with fire, they will most likely flee. Harpies are also strong enough to carry another human being in their arms.
- In Greek mythology, Harpies are best known for their cruelty and their habit of stealing food;
- The Harpies that appeared in both seasons of the series appear to be quite shallow, which may indicate a trait in the species and not in the individuals. For example, the two Harpies that (somewhat) enjoyed Jake's party in "Halloween Bash" keep speaking of the other guests with a snobbish tone. The one that appeared in "Magic Enemy #1" abandoned the fight because the tip of its tail was burned (but undamaged) by Jake's fire breath;
- Harpies shriek like hawks;
- The American Harpy Eagle is named after this mythological creature.
- Although the Harpy is constantly hungry and is always on the verge of starvation, it is an immortal being, incapable of ever dying.