The Harpy Twins are harpy sisters with a strong bond. They kidnap and mate with men from the nearby Happiness Village under the orders of Queen Harpy to prevent their extinction. The older sister is protective and tutors her younger, inexperienced sister.
In Chapter 1, as Luka tries to subdue the Queen Harpy at Harpy Village, the twins run into him, with the younger sister deciding to be his first. Like with the Harpy from before, his attacks prove worthless as they fly away, and like before they do not hold down his arms when trying to mate. After a small fight, the younger sister cries out and calls Luka a "meanie" for trying to "kill" the older sister. Feeling guilty, Luka retreats, the two not giving chase.
After resolving the issue between the humans and the harpies, the two work hard in Happiness Village so they can play when finished.
In Chapter 3, after Luka repels Ilias's invading forces on Happiness Village, both sisters reveal they survived by playing dead.
