The Medieval Knights' Training Ground for Murder (中世騎士殺人修練場 Chūsei Kishi Satsujin Shūren Jō), originally Chamber of the Two-Headed Dragon (双首竜の間 Sōshuryū no Ma) in the WSJ release, is the thirty-second chapter of Phantom Blood and the thirty-second chapter of the JoJo's Bizarre Adventure manga.
As Jonathan and company glide to safety on the giant leaf made by him and Zeppeli, Poco asks how they managed to make it. He further inquires if the two of them are magicians or angels to be able to perform such feats. Speedwagon adds to the conversation and quickly inquires about Zeppeli's past. Zeppeli obliges him and begins to explain his past concerning the Ripple.
After Zeppeli's first encounter with the Stone Mask, he had sworn to find it, and searched the world for it without a clue as to its whereabouts. Two years into his search, his search eventually led him to India, where he found a young man who called himself a doctor. He witnessed this doctor, heal a patient's leg wound simply by touching it, as if by magic. Zeppeli saw that the power the doctor had just used was the opposite of the Stone Mask; giving life instead of stealing it. So Zeppeli asked how the doctor got these abilities, and was told to go up the Nuu River and look for his master Tonpetty. After arriving at Tonpetty's temple, Zeppeli approached him to shake his hand. As Tonpetty took his hand, he gave Zeppeli a prophecy warning him of his imminent death if he were to train under him.
Zeppeli reveals all but the prophecy to Speedwagon and the others. Suddenly, Tarkus jumps after them from the cliff in an attempt to catch them and damages their glider. Thinking quickly, Jonathan shouts for them to all jump to the nearby building in the cliff side and abandon the leaf. Tarkus crashes into the side of a tower as the rest of them make it to the safety of the building.
Jonathan believes the Tarkus should be dead or immobilized from the fall and the crash; however his hopes are dispelled when the zombie emerges from the hole he made in the side of the tower. Zeppeli reminds the group that Dio is their true objective and tells Jonathan to enter the building to find a place where Poco can hide safely. As Poco and Jonathan enter the doorway, the boy advises against going in, saying that they should be wary as it was the former knights' training ground and likely riddled with traps. Shortly after, Jonathan opens the door and a neck brace on a chain hooks itself to him and pulls him up to the ceiling.
Tarkus, had entered the room. He recognizes it as the “Lair of the Two-Headed Dragon" where he had fought death matches over 300 years ago. The nostalgic Tarkus puts on a neck brace identical to Jonathan's attached to the same chain.