Tadanaga's Change of Heart is the seventh episode of Basilisk ~Ōka Ninpō Chō~.
As the black castle towers in the forest near the tea stand, Hachirou is called to meet Tadanaga, where he learns the truth about Tadanaga's thoughts during the incident four years ago.
Namenba had infiltrated the Edo Castle. She recalls her conversation with Gorone and the message from Geiin about the attack of Kurokuwa and Joujinshuu, which would make Tadanaga believe its ordered by the Shogun. But as its too obvious, he believes it may be to turn Tadanaga's heart evil, and cause a treason. As they need to ask the Shogun if there is connection, Namenba says there is a way and heads for Edo. In Edo Castle, as she sneaks around, she gets attacked by Kurokuwa members, but easily kills them. She notices one was killed by someone else. She reaches Iemitsu's bedroom and makes him drink a potion. She asks him about Kurokuwa and his order to delay Tadanaga, but he says he didn't gave such order. She then asks him about Joujin, but Iemitsu states he doesn't know that name. Namenba then escapes and on the castle's roof she meets Hadaebō, realizing he was the one that killed the other Kurokuwa member.
The girls discuss what to do with the castle as Hibiki feels its related to Joujinshuu. The boys were gone from yesterday and they decide they need to move, but Hibiki orders them to stay and wait for Namenba.
Hachirō meets with Tadanaga, who asks him if he knows why he is there and Hachirō states he doesn't and is there as the former leader of the Five Treasures. Tadanaga guesses he is aware who Joujin is and that he was present when Joujin killed the Five Flowers and Five Treasures just to show him his power and pushed him to do something. Tadanaga then shows a drawing of the castle that appeared, Murakumo. He gave Joujin money to make an imperial carriage for his mother's memory, but six year later, he sees this castle. Tadanaga decides to tell something that only he and Hachirō will know, he reveals that Joujin encouraged him to rebel against his brother and promised him to keep his mother alive, and her health improved, but still died six months later. He then tells him that two years ago at Sengen Shrine, he took a rest and the forest started to move. As monkeys came attacking them, he felt mocked and in order to stop the forest moving, he ordered his men to kill the monkeys. Tadanaga requests that Hachirō destroy Murakumo castle and slay the Joujinshuu, but Hachirō refuses, not wanting Tokugawa to take anymore advantage of them and reminds him of the twenty Iga and Kōga ninjas that died to determine the next Shogun and the Five Flowers and Treasures, died for a fool like him. Tadanaga gets angry for Hachirō refusing and states he won't leave alive. His men then enter the room and surround Hachirō, as they were lowering their heads to not meet Hachirō's eyes, Saizō using his ability makes them look into his eyes and connects it with Hachirō's eyes. Under Hachirō's dojutsu, the men kill each other.