Ooka Tadasuke (大岡忠相, Ooka Tadasuke) or his real name is Ooka Echizen no Kamitadasuke. He is Magistrate of the Edo South town. A brilliant man, heavily involved in city policy and he is said to be the smartest man in Edo.
Ooka wears a samurai themed outfit while wearing a straw hat and glasses.
Ooka is a man who follows the principles of the Bushido (the way of the warrior). Ooka is a calm, tactical and careful person in every situation. Ooka also shows great loyalty towards Yoshimune Tokugawa. His favorite phrase is "it is wrong" when someone did something he believes will affect a mission.
Not much is shown about Ooka's past except a short flashback of him in his younger days when he saw the Insect Magistrate for the first time.
Ooka Tadasuke is the samurai sent to protect the Mushibugyo while she is on her journey to retrieve her powers at the Kishuu well. While Ooka, Kuroageha, and Jinbei are on their journey, Jinbei does many childish things causing Ooka to disapprove of this and say he is wrong. After repeating this so many times Ooka tells Jinbei that he is not the right person for this job. Ooka tells the Mushibugyo and Jinbei that if he does one more thing wrong he will request that Jinbei will return to Edo. When they reach the Kishuu gate, no one is allowed to enter. Ooka tells the gate gaurds that if they do not allow them to enter all the gaurds must commit seppuku. The gaurds still refuse and say that the lord Munenao has requested this, Ooka is shocked to hear this and decides to leave for another gate and sneak in. They attempt to get to the other gate by crossing a mountain path. When they reach the second gate they hide in the bushes, but when the Mushibugyo steps on a stick the gaurds hear it and thier hiding spot is revealed. Ooka, the Mushibugyo, and Jinbei run, with no escape Jinbei is forced to draw his sword. ooka tells Jinbei that fighting is pointless, Jinbei tells ooka not to worry and instead he cuts down three trees as a distraction for them to hide on top of a nearby tree. When night falls an Insect man appears and murders all the gaurds. the insect man introduces him self as Nedzu jinpachi and tells Ooka, Jinbei, and the Mushibugyo to come out of thier hiding spot. Jinbei is about to draw his sword when Ooka stops him, saying that he is wrong and he must not let feelings interfere with his task. Jinbei says that these are not feelings and that the Insect man is evil and he must be killed. Ooka asks Jinbei what would happen if something happened to the Mushibugyo? Jinbei frowns and decides to listen to ooka. But the insect man attacks them first and they dodge the attack. In response jinbei attacks the insect man but the Insect man parries all his attacks. jinbei tells Ooka and the Mushibugyo to hurry up and go to Kishuu. Ooka objects but the Mushibugyo allows him to fight the Insect man. While Jinbei is engaging combat with the insect man, Ooka asks the Mushibugyo why she chose Jinbei for the task of protecting her. The Mushibugyo resonds saying that he is the most suited to the task because he is mistaken as for her identity and she hoped to make memories. Ooka is puzzled as to her feelings but that does not stop him from being loyal to her. When Ooka cuts the gate down, the Mushibugyo tells Jinbei to hurry and and the battle. Jinbei complys by finishing of the Insect man with his Mt.Fuji hammer. When they come upon a small village in Kishuu, Jinbei sees an old lady in need of help. Jinbei arives to help her but Ooka stops him saying that everyone in Kishuu is thier enemy. Jinbei ignores this and goes help the Lady. The Lady pulls out a knife and tries to kill Jinbei, after he dodges the lady calls all the villagers over and they surround him. Jinbei breaks throught the formation and the villagers pursue him. When Jinbei hides between two houses a child villager uses his small scythe to impale Jinbei's arm. When he does the child calls over the villagers but bandits appear. when the child is about to be run over by the bandit's horses, the Mushibugyo saves the child by pushing him out of the way. When the bandits see her, they attack her but Ooka cuts thier katanas in half. When the bandits are about to retaliate Ooka cuts all thier hands off instead of killing them because of the Mushibugyo's request. Later all the villager surround them and capture them. Instead os killing them, the villagers hold a celebration because Ooka got rid of the bandits. Bizen, the village chief does not celebrate saying that they must kill them. The old lady tells him to stop it but bizen says he has too or everyone will be killed. Jinbei says that he must not die here but Bizen does not care. When Bizen is about to kill him someone shouts saying that the insect men are here. Bizen stops his move to kill him and tells the villagers to hide in thier homes. Mochidzuki and Unno Rokurou the insect men arrive telling every one that the "criminals" are hiding in thier area. When the villagers hide and ignore them Unno holds Irori hostage and Mochidzuki tells everyone that something bad will happen to her if they do not say something. Jinbei interrupts the Rokurou pair and attacks Uuno, therefore freeing Irori from her hostage position. Mochidzuki attacks Jinbei but Uuno draws Jinbei's attention on him while Mochidzuki slashes him on the back and Unno crushes him. Ooka walks up to Uuno's roly poly form and knocks on it. Ooka tells Jinbei that wasn't he going to stop the insect men. As he says this Jinbei carrys Uuno on his back and throws Uuno. Ooka and Jinbei fight together while Ooka takes on Mochidzuki and jinbei takes on Uuno. The battle ends quickly with Jinbei and Ooka victorious. Irori walks up to Jinbei and thanks him, Jinbe responds her by saying that he is glad that she is alright and Irori falls in love with him. jinbei, Ooka, and the Mushibugyo are preparing to leave until Bizen stops them telling that they have to tell them why they are here. Later, Ooka is seen talking to the lord of the area, Yamagatake. Ooka is requesting help from the lord to inflitrate Wakayama castle. Yamagatake agrees to help them only if Ooka promises to not let the insect men harm any more people. After discussing the plan with Yamagatake he explains it to Jinbei. Ooka explains that the snow group (consisting of Mugai, the Mushibugyo, and Yamagatake) responsible for retrieving the Mushibugyo's power, the moon group (consisting of Irori, Bizen, and the Iwamatsu villagers) are responsible for civillian evacuation, and lastly the flower group (consisting of all the city patrol members except Mugai) are responsible for buying time for the moon group.
Ooka battles Sanada Yukimura on the top floor of the Kishuu castle.
- Ooka Tadasuke is named after a real Japanese samurai Ooka Tadasuke, who served under Tokugawa Shogunate, Yoshimune Tokugawa as Magistrate of Edo.