Harpia Π7 (Pi7) was a Ghost Mechanical Beast featured on Episode 74 of the original Mazinger anime. Resembling the general outlook of the harpy, she had light/mid/dark lavender in colors. She had four wings, the top fore-wings had launchers which fired explosive feathers from them, her feet were talons, capable to rip apart enemies, and her mouth was a missile launcher which fired rockets, while the breast like plates on her chest is capable to fire laser beams as well Magnetic Beams from the talons, that attract an enemy on to her, as well fire Immobilizing Ray from its eyes, though the effect can be brief. Harpia is infamous for been the Beast who destroys Sayaka's Aphrodite A in the show, which is later replace by Diana A.

Harpia appears at the start of the episode, attacking the Borot gang, who were out on a Bike Ride, though she continues on her way. The Photon Lab detects her and sends out Sayaka on Aphrodite A to investigate, as Koji was out with Misato (Boss' cousin) – naturally Sayaka been jealous of it. As she explores the crater on Mount Fuji, Harpia comes out and attacks – the two fire rockets at each other, but Harpia uses her explosive feathers and Chest Ray, and blasts Aphrodite's right arm off, Sayaka sends a distress to the Lab. In the meantime, Koji spends time with Misato, teaching her how to ride a bike, Boss tries to warns him, but he ignores it, Misato loses control of the bike, crashing onto Koji and wounding him. In that moment Yumi calls and warns of Sayaka's situation as Archduke Gorgon makes his way, ordering Hell to ready his troops at his command. Koji, Misato and the Borot gang return to the lab, where Yumi learns of the accident, and stops Koji from going to battle, Yumi then asks for Nuke and Mucha to help Sayaka, the two accept and go out on the Borot, without Boss.

On the way, Borot encounters Archduke Gorgon, who introduces himself for the first time to any of the main protagonists in person. Borot tries to run away, but Gorgon shows his might by grabbing hold of it with his whip. Aphrodite A appears and scares Gorgon away with her rockets, but Harpia shows up, attacks and captures Borot with its Magnetic Waves, these begin to screw with Aphrodite's systems. Harpia throws Borot and Nuke and Mucha are knock meanwhile Gorgon makes it to the Photon Power lab and challenges Mazinger Z. Hell realizing was wrong with the fact Z hasn't been launched, orders Ashura to attack lab, as Harpia continues to tear Aphrodite apart Boss arrives and takes control of the Borot. The facility enters on high alert as the monster approaches and Koji goes to fight despite his wounded state, recognizing his fault under the circumstances – Bood emerges and Ashura launches a battalion of tanks to attack the lab. Yumi calls for the help of Borot and Aphrodite A, but Sayaka is reluctant, as at this point she is well convenience Aphrodite is in no condition to fight. As Ashura arrives to launch his/her attack Borot arrives and destroys the tanks, but Harpia blasts Borot's head off, taking it out the fight. Koji takes off and activates Z, when Sayaka learns this, she runs back to the lab to help.

Mazinger deals with the Tanks and fights Harpia, and uses the Iron cutter and rips the legs off. Harpia then pins Z down with her laser eyes, which immobilizes it. Harpia fires her Feather Bombs, but Aphrodite intervenes and blocks them, getting hit by then, Sayaka pleads to Koji to not let Aphrodite die in vane as Harpia unleashes her laser beams, hitting the feather bombs, the explosions rip Aphrodite apart. In revenge, Koji dispatches Harpia with Iron cutters (cutting the wings off, then ripping the Beast in half) and Optic Beams, destroying the rest. An irritated Gorgon then blames Ashura, for having intervene and costing him the victory.

Koji then runs back to the wreck of Aphrodite A, as Sayaka walks out unharmed, but emotionally affected. She and Koji bid their farewell to Aphrodite A as Mazinger Z's Hurricane Winds lift the remains, which are lifted and disintegrated into the sunset.

Koji then runs back to the wreck of Aphrodite A, as Sayaka walks out unharmed, but emotionally affected. She and Koji bid their farewell to Aphrodite A as Mazinger Z's Hurricane Winds lift the remains, which are lifted and disintegrated into the sunset.