Sakaki is a 29-year-old extremely powerful, self-proclaimed 100-dan karate master. He claimed not to take disciples at first, but gradually grew to like Kenichi and is always eager to train him. He has a soft side which he tries to hide behind his tough guy attitude, and is usually the one worrying about Kenichi the most despite acting like he does not care. He is also a terrible liar and often fails to hide his concern for Kenichi. He likes to gamble and can usually be seen drinking alcohol. He is also "fluent" in English after brawling all over the world. He is the fiance of Jennifer Grey(even though Sakaki was drunk and Jennifer was a child at the time he proposed). He is an old friend of Christopher Eclair, a Yami member. Sakaki, Christopher and Mycroft (Possibly a reference to Mycroft Holmes, Sherlock Holmes's older brother) used to team up to fight against the mafia and help the FBI. He refused to kill or use old people or children as hostage. Christopher, tired of Sakaki's methods, tries to ambush him, but Sakaki buries him alive in a desert (when Kenichi learns this, he imagines them being tied up in a hole while Sakaki uses a bulldozer, claiming that the two aren't even good manure). The majority of the underground fighters are scared of Ryōzanpaku and Sakaki in particular. There is little known about his past or why or how he became a martial artist especially of his status. Though his master was said to be a master of "Sei", which means that Sakaki's master was a very logical person at heart though to get him to his level, he must have undergone through unimaginablly hellish training.

Hayato is Miu's grandfather and the undefeated elder of the Ryōzanpaku Dojo, who is said to have beaten 500 Shaolin masters to near death. He is also known as the 'Invincible Super Man' (無敵超人, mutekichōjin?, lit. 'man with no equals'). His kicks have speeds that are still a blur even when viewing a replay of it at 1/1000 of the normal speed. If necessary, he is able to intimidate the other masters in order to maintain peace. Even using just 0.0002% of his power, he can easily overwhelm both Kenichi and Miu at the same time and rip a tree in half. He was able to defeat a master level opponent in D of D tournament with just one finger. Prior to building the dojo, he and his granddaughter had traveled around the world in his quest for peace. He has 108 special techniques so far and can copy any move an opponent uses against him, like Kenichi's 'Saikyou(Strongest) Combo' and 'Saikyou Combo 2' , Soutenshu and Miu's 'Hyōi Kazekirihane'. He knows Seikūken and is the creator of "Ryūsui (flowing water) Seikūken" which Kenichi learned from him. However, his most used technique seems to be the 'Human Shuriken.

Dark Schneider is the most powerful sorcerer in the world, which he almost completely took over before being imprisoned in the body of a little boy by Grand (or Great) Priest Geo. Rushe is soft spoken and had a crush on Yoko, which carried over to Dark Schneider. Rushe and Dark Schneider share the same soul, which means they love what each other loves, but that is where it ends: Dark Schneider can be incredibly evil, heartless and lecherous, whereas Rushe is faithful, quiet and friendly. Dark Schneider is immortal (though whether this is conferred upon Rushe is unclear) -- he can resurrect himself through will-power alone. In the English version, he is also called the Mage of Fire, and, in the Japanese, The Exploder Wizard. Whenever Rushe is kissed by Yoko, Dark Schneider is released, and when Dark Schneider is kissed, Rushe is released, and so on, though Dark Schneider can break the seal himself when extremely angry, and he can control Lushe's body at certain times of night (re-gaining his powers for a while in the process).

Главен лошковец в Арабастра арката и съюзник през войната, Крокодила е бивш пират, Шичибукай, затворник и към днешна дата с неизвестни цели се намира в Новия Свят със своя подчинен Даш Бон.
Манипулативен, безскрупулен, убива без колебание, преди да бъде победен от Луфи и свръхамбициозен. Подлага цяла една страна на терор криейки се под маската на mr 0, с цел да придобие мечтаната от него сила, като трябва да отбележим, че междувременно публичната му роля е на неин защитник.
Изял е дяволския плод Suna Suna no Mi, което ще рече, че е логия тип пясък. За него се знае, че е овладял до край способностите на плода си, не е показано да притежава хаки. Въпреки малката сума давана за награда за главата му от Правителството (преди да стане Шичибукай) Крокодила е сред елита на света на One piece, един от "сребърните медалисти" , хората неуспяли да преборят Белобрадия, в опитите си да станат Императори или Крал на пиратите.

Dark Schneider