The Ninja (ザ・ニンジャ) is a character from Kinnikuman and its sequel Kinnikuman Nisei. In the English dub of Ultimate Muscle he is renamed Ninja Ned (although, when he mentioned by Sunshine during the match between Mantaro and Checkmate he's refer to as The Ninja) and is said to be an imposter from The United States of America who studies ninjutsu in his spare time.
- Classification: Akuma Choujin → Seigi Choujin
- Homeland: Japan
- Age: 24, 26 (Throne Arc), 60 (Nisei)
- Height: 190 cm
- Weight: 115 kg
- Chojin Kyodo: 3,600,000 Power
- Trademark Techniques: Hell's Inferno, Waterbird Feather Ring, Binding Spider Web, Jungyaku Jizai no Jutsu, Tensho Jizai no Jutsu
- First Appearance: Golden Mask Arc
- Masashi Hirose in Kinnikuman
- Sho Hayami in Kinnikuman: Scramble for the Throne
- Hiroaki Hirata in Kinnikuman Nisei and PlayStation 2 games
- Ted Lewis in Ultimate Muscle (English Dub)
A ninjutsu chōjin. Nicknamed Shōnetsu Jigoku (焦熱地獄 Tapana Naraka (Scorching Hell)). He was one of the Devil Knights who served Akuma Shogun and stole the Golden Mask of the Kinniku Tribe. When the Devil Knights retreated into Warsman's body for the Five-Story Ring battle, he fought Brocken Jr. Although he had the advantage throughout the fight, Brocken won in the end when he threw the both of them over the side of the ring. As they fell, Ninja disguised himself as Brocken so Robin Mask (in the next ring down) would save him. Robin only had time to save one Brocken and, fortunately, he grabbed the real one, causing Ninja to be killed when he was impaled on Junkman's spikes.
The Ninja appeared again, alive and reformed, as a member of Kinnikuman Soldier's team during the survivor series for the throne of Planet Kinniku. He fought Satan Cross and was killed by his Triangle Dreamer, but was brought back to life along with the rest of Team Soldier by Kinnikuman's Face Flash.
Years later, The Ninja forms the Chōjin Untouchables (超人特別機動警察隊(アンタッチャブル) ) with Ataru Kinniku (Soldier). He interrupted Mantaro's fight against Hanzo, who was captured by the Ninja after his best student, Kokumo, was killed. At the end, Hanzo kills The Ninja, who later helps Mantaro through the fight as a spirit.
His spirit reappears during the Demon Seed Arc to encourage Hanzo during his fight against Gepparland. Whether or not he is revived by the Reborn Diamond with the other fallen Seigi Chojin is unknown as he has not been seen since.
- Jungyaku Jizai no Jutsu (順逆自在の術 Order and Betrayal At Will)
- In the midst of an opponent's attack, The Ninja moves at super speed and switches places with his opponent.
- Ninpō: Kumoito Shibari (忍法・蜘蛛糸縛り Ninja Art: Binding Spider Web)
- The Ninja grabs onto the ring ropes one by one and wraps them around his opponent. With his opponent trapped and defenseless in the middle of the ring, he begins attacking them.
- Karada Ayatsuri no Jutsu (身体あやつりの術 Body Manipulation Jutsu)
- Tensho Jizai no Jutsu (転所自在の術 Area Transfer Jutsu)
- The Ninja takes out a sheet that covers the entire mat and gives it a new surface, from water to a volcano opening.
- Shuriken Stomping (手裏剣ストンピング)
- Ninpō Kaojashi (忍法顔写し Ninja Art Face Copy)
- Ninpō: Suichō Urin no Jutsu (忍法・水鳥羽輪の術 Ninja Art: Waterfowl Feather Ring Jutsu)
- The Ninja produces hundreds of feathers from within the wrestling ring, has them float in ring shapes and then envelope and stap the opponent.
- Gōka Urin no Jutsu (業火羽輪の術 Fiery Feather Ring Jutsu)
- Haiten Dengaku Zashi (背転田楽刺し Spinning Back Skewer)
- Yami Kumo Otoshi (闇蜘蛛落とし Dark Spider Drop)
- Ninpō Zettai Reido (忍法絶対零度 Ninja Art Absolute Zero)
- Ninpō Hyōka Tomurai Shibari (忍法氷華葬い縛り)
- Wangetsu Shuriken Sashi (彎月手裏剣刺し)
- Wangetsu Dengaku Zashi (彎月田楽刺し)
- Submitted by: Kobayashi of Tokyo.
- Theme Song: "Japanese Magic (ジャパニーズ・マジック)" by Yurikago Kai & Kōrogi '73
- 1st Kinnikuman Nisei ~All Choujin Dai Shingeki~ Popularity Contest (12th Place)
- One of the Six Devil Knights
- Choujin Blood Brigade - Advance Guard
- A True Ninja of Japan (日本の正統忍者, Nihon no Seitou Ninja)
- Red Hot Japanese Ninja (灼熱の日本忍者, Shakunetsu no Nihon Ninja)
- Policeman of Crying Children and Silent Tenacity (泣く子も黙る執念の警官(ポリス), Nakuko mo Damaru Shuunen no Porisu)
- The Man of A Thousand Jutsu (千の術を持つ男, Sen no Jutsu wo Motsu Otoko)
- Win/Loss Record