This article, Tetsu, is the sole property of Subrosian. Any edits in this page without his permission will suffer the wrath of the Monster Trio. You have been warned.

Age 34
Gender Male
Species Human
Blood type Unknown
Birth date Unknown
Height 6'2"
Weight 220 lbs.
Birth place Unknown
Occupation Pirate
Epithet Iron Mammoth
Crew Black Hole Pirates
Position Helmsman
Family Unknown
Bounty Bsymbol1025,000,000
Dream Unknown
Devil Fruit
Japanese Name Tetsu Testu no Mi
English Name: Iron Iron Fruit
Meaning: Iron
Type: Paramecia

"Iron fortitude." -Subrosian

Tetsu the Iron Mammoth (テツ, Tetsu) is the Helmsman of the Black Hole Pirates. He ate the Tetsu Tetsu no Mi.


Tetsu is a large man, standing at six foot two and weighing 196lbs. He wears a dark blue 'v' neck shirt with a few buttons on it. His hair is short, orange, and curly but is covered by a blue and white striped bandanna. A few curly strands stick out in the front. He also wears a pair of simple brown pants and shoes with a wool lining. Tetsu's skin color is a light tan color.

However, his physical appearance changed considerably when he ate his Devil Fruit. Upon taking the first bite, his skin changed to an iron plating, making him appear as an actual iron human. As a joke, he wears an iron mask over his iron face with a rectangular box for a mouth and glowing yellow eyes. His hair was turned iron as well, giving it a solid and metallic appearance.


Tetsu is a seemingly absent minded person, as he often clumsily stumbles into objects and people, but he is a vicious fighter and takes no chances with his opponent. He has low tolerance for people that are insubordinate to either him or his captain, though he greatly fears Ryoku and obeys him out of both respect and fear.



Tetsu is the one who does all of the grunt work for Ryoku, acting as his Helmsman and it is possible that he is considered his First Mate as well, though it is not known.

Kedamono Jeran

Tetsu has made an enemy of Jeran because he attacked him viciously and left him with a scar on his left rib from where he tore him open with his new claws.


Due to his massive size, Tetsu is an incredibly strong person with seemingly super human strength.

Devil Fruit

Tetsu ate the Tetsu Tetsu no Mi, a Paramecia-type fruit that turned his skin into a permanent state of iron plating that defends him from swords, bullets, punches, or any kind of attacking force.


Six years prior to the current storyline, Tetsu accidentally bumped into Jeran and knocked the barrel he was carrying into Rydia's fruit stand, causing it to crack and drop the Garou Garou no Mi onto it. After Jeran ate it, Tetsu came back and demanded to know what he had done with it. In anger, Tetsu attacked Jeran and was only successful in catching a claw slash to the ribs. Shortly after, Ryoku showed up and crushed them both under an intense weight. However, when Ryoku allowed Tetsu enough leeway to get up, Jeran took it as an opportunity to escape into the mountains.

A Grudge Six Years in the Making

Tetsu was about to fight Jeran, but Ryoku stepped in and told him that Jeran was his prey. He told Tetsu to fight the rest of the Straw Hats on their ship. He was last seen battling Sanji and Zoro along with a cadre of Black Hole pirates while the two were quarreling over which one should fight Tetsu.

His fight with Zoro and Sanji never took off, because Luffy interrupted the two of them and took Tetsu on himself. He battled Tetsu for a short time, knowing he was unable to harm him. Sanji came into the fight at Luffy's request, kicking him several times to get his mouth open and Luffy attacked to hurt his pride, grabbing his uvula to make him throw up. Tetsu was angered, saying that if Luffy did not get serious, he would soon suffer due to that lifestyle. Luffy was about to get serious against him and use his Gear abilities, but Sanji kicked him to the side and took the fight over. Using Diable Jambe, Sanji caused severe burns to Tetsu by scorching his iron skin to the point he could not take it anymore and jumped into the water. The crew that was left standing had to jump in to save him. It can be assumed that Tetsu left with the rest of the crew when Ryoku left the naval battle.

Major Battles


  • The character Tetsu, and this article were created by Subrosian.
  • Tetsu is the only known character so far to have his name match with the Devil Fruit he ate, both of them being Tetsu. It is a running gag with him to be made fun of for his name, Tetsu no Tetsuningen. Tetsu the Iron Human.