|This article contains information that only comes from the anime, not the manga.|
For more information on this, see Filler Episodes.
Then as now, Henzo has a potted hairdo, with the difference that as an adult he still wears a beard with it. He has a normal build and wears a colorful shirt under his lab coat. Otherwise he is still in possession of dark jeans and sandals.
As a child, Henzo was a rather gentle soul, so he did not immediately dare to jump off a high rock into the water like his friends. However, those friends and their idea of being pirates gave him the courage to overcome such situations. Even though all his comrades expressed wanting to become pirates, he was the only one who had reservations about it. He believed he was too weak to fight. Rapanui Pasqua often built him up though, after all Henzo would be good at inventing things that would be useful in the event. When he was trapped in the Rainbow Mist and encountered Rapa Nui, he fell to his knees in front of him and apologized for failing to save them after 50 years of research.
Henzo is a brilliant mind, even though he is called crazy by the residents of Ruluka. They are also angry with him because his rainbow tower project consumes a lot of taxes that the residents have to pay for every little thing. He is always developing new inventions, such as a hovercraft, but it is powered by a pedal. Furthermore, the electric suit of Rake comes from him.
When they were children, Henzo, Rapa Nui, Pukau, Isoka, Rongo and Akibi often met at a big rock in the sea, went swimming and talked together around the campfire in the evening. One afternoon, when they met together once again, they saw from afar how the town was on fire.
Worried for their families, they ran to it and met the captain of the attacking pirate gang, Wetton, of all people in the town, who was having fun chasing the children. Rapa Nui led them to the harbor, where his plan was to grab a ship and escape. But the pirates had destroyed all the ships, so the children climbed aboard Wetton’s pirate ship. The latter jumped in after them and tried to grab the children. He hurled his axe and managed to destroy the steering wheel.
Unfortunately, the ship was heading straight for the Rainbow Nebula, which Ian, who was left alone on the ship, was not at all pleased about. Wetton still tried to fight the children, though. Henzo unexpectedly threw himself at him and they both fell off the ship before the ship even reached the Rainbow Nebula. His friends and Ian thus sailed into the mist, where they did not age, and Henzo and Wetton swam back to the city.
Acquaintance with the Straw Hat Pirates
He made his first appearance when the Straw Hats went ashore. There he intercepted Usopp and Robin and asked them if they had passed the Rainbow Mist. Usopp had no idea what he was talking about, but a light seemed to go on for Robin. While sharing a meal with Luffy, the man introduced himself as Henzo, a scientist who was researching the Rainbow Nebula. Robin showed him the book she had from Arabasta, titled “Rainbow Nebula”.
Written it would be 40 years ago and the author was unknown. After Robin said that the book said that El Dorado, the City of Gold, was in the Rainbow Nebula, Henzo disagreed. It would only be a legend and anyone who went there never returned, just like his friends. The waiter advised the straw hats not to take everything Henzo told them at face value. He was just Mayor Wetton’s lapdog.
Shortly afterwards Flip, son of Wetton, came in and demanded taxes from the citizens. While doing so, he discovered Henzo and teased him about his research with the Rainbow Nebula. Eventually Flip left the inn again, but not without demanding taxes from Usopp for the food. Henzo and company also left again. The cook followed them, and told the three straw-hatted pirates that they had better avoid further dealings with Henzo. Robin countered that this was their captain’s decision.
They continued to wander through the city until they heard the report that a galleon was coming into port. When Henzo spotted her at the harbor, he took a hovercraft to her. He examined the entire ship, but found no one. The Going Merry approached the galleon and the Straw Hats also came aboard. Robin noted that the ship would appear as if there had been someone on board not too long ago, even though the ship was an older model. Other than the fact that the ship was already 50 years old, Henzo couldn’t explain much as the radar he always carried was off. On deck, they spotted a colorful spectacle of clouds, which Robin identified as the Rainbow Nebula. So they all boarded the Going Merry and headed into the fog and immediately arrived at a ship’s graveyard.
In the rainbow mist – meeting old friends
Luffy and Usopp explored the area and also found a box full of diamonds and other gems. But suddenly, ghosts appeared and arrows were shot. Thanks to Luffy’s help, it was quickly revealed that behind that “attack” was a group of children who called themselves the Pumpkin Pirates. When they were busted, Rapa Nui threatened to detonate a hand grenade if they didn’t let them go. Henzo recognized his old friends in the children, who had not aged a day in the rainbow mist. Rapa Nui was unsure at first if he was really Henzo.
Even after the scientist exposed the hand grenade as nothing more than a fake he had invented, Rapa Nui remained skeptical and eventually took flight with the others. As they rejoined his friends and all ate, Henzo came to the Rapa Nui and apologized for his failure, for he had not been able to save them. Henzo’s Den-den Mushi rang and Flip was on the line.
The latter was to bring the scientist the device he had invented in the Rainbow Nebula. When Wetton’s name was mentioned, Rapa Nui was furious and called Henzo a traitor for working with the pirate who burned their city to the ground. Usopp settled the dispute and just as they were about to make up, Luffy’s too much momentum accidentally took Rapa Nui to the edge of the Rainbow Nebula, where they were stuck for now. Ian was released by Rongo and was thus able to blackmail the others, wanting the boat with the rope to the outside from Nami, who had arrived just before. Ian finally escaped the fog that way.
Escape from the fog
As Henzo feared, Wetton activated the rainbow tower, which was a tube leading into the mist where Wetton had his troops search for the treasures. Wetton, seeing that he stood no chance against Luffy, used a lever to explode the tower. The explosion made the fog unstable, so they had to get out of it quickly. The air blast from the cannons fired from the wrecked navy ship finally got the Going Merry outside. There the navy appeared, the leaders of the unit being the aged Rapa Nui and his friends. Henzo, recognizing them, was overjoyed to see them again. The naval unit arrested the criminals of Ruluka. The locals were happy about this and asked Henzo to stay here and investigate further, as the Rainbow Mist might reappear.