Pluto

''This article is about the character. For the manga, see here.'' Pluto (also known as Bruton in the 1980's version) is a giant metal fighting robot with horns and red stripes on his face.

He was built to destroy the strongest robots in the world, including Astro. At first he wants nothing more than to furfill his duty but soon he realised that programming isn't everything and friended with Astro. He has Kokoro.

He once captured Uran and she was mad but then they got along.

1980's series
Known as Bruton in the 1980's series dub, he was created with the sole purpose of defeating the worlds strongest robots.

Plot
A Sultan wants to be the ruler of the robot world, so he hires a scientist to build a robot. It must have 1 million horsepower, plus various powers in order for it to become the "Strongest Robot in the World". Named Pluto, his first target is a Swiss mountain robot with 135,000 horsepower named Mont-Blanc, which was a easy victim as Pluto was a complete stranger to him and he did not suspect the attack. With Mont-Blanc finished, Pluto then goes on to fight Astro, who was not at home (plus Professor Ochanomizu insisted on Astro not fighting, much to the annoyance of Uran). As Astro himself does not engage in battle, Uran pretends to be Astro in order to fight Pluto however is no match for Pluto's horsepower and strength. Overcome, Pluto ho lds Uran captive as a way of forcing Astro to fight. Enraged, Astro follows in hot pursuit. Meanwhile, Pluto then goes to fight Molnar, a fearsome beetle-like butler robot, which is no match for Pluto's strength, being defeated almost instantly. Seeking Astro, he and Astro again meet (which so happens to be in Turkey) which by chance is the residence of the next robot, Brando. Sharing similar strengths and weaknesses, Pluto just defeats Brando - and only just - and he also was a consequence was heavily damaged, and shall die if his masters do not come instantly. In order for them to come, a button on his chest has to be pushed which sends a distress signal. However, as there is no-one else nearby and he himself is unable to move his arms, the only way for the button to be pushed is if Astro pushes it. Pluto quickly hands over Uran, and begs Astro to push the button. After much thought and consideration, Astro agrees. His masters come and collects Pluto and plants a suicide bomb in his chest; should someone defeat him, that someone would also be destroyed. Pluto then faces his next target, a German robot detective named Gerhardt, made out of a unique material named "Zeronium", which takes the form of a protective metal alloy. Gerhardt's machine guns prove ineffective against Pluto's shield, and he is also destroyed. Astro, who was informed of the battle beforehand and sees the result of Gerhardt on the news, realises that Pluto must be stopped as no robot is a match for Pluto, however realises that Pluto is simply too powerful for even him: so he thinks up a solution; ask Ochanomizu to increase his horsepower instantly. Flying over to the ministry of science, Astro finds Ochanomizu "already busy", since he has tracked down Pluto's hideout by monitoring his movements, and flies over by plane to the hideout. Unable to convince the Sultan, he is held captive and the only way where he allows him to go is when Astro fights Pluto. Ochanomizu reluctantly agrees, and Astro and Pluto meet in the desert, unluckily right in the middle of an oil field. If the oil explodes, the impact would be massive: he refuses to fight, and as a result Pluto holds Astro in his hands and prepares to tear him apart, but then spares his life as he remembers that Astro saved him once. Reminding Astro he would only do it once, Pluto takes off and fights Hercules, a Greek gladiator robot with a high sense of nobleness and bravery. He soon becomes another victim of Pluto. Meanwhile, at Astro's place of residence, he receives a phone call from the southern continent. The caller is Epsilon, which except for Astro the sole remaining member of the strongest robots in the world. Epsilon is a robot with a gentle personality that takes care of kindergarten children. As he needs sunlight, Pluto promptly chooses their day of the battle on a stormy day, therefore Epsilon would not be at his full strength. Epsilon also is destroyed after risking his life to save a lost infant. Astro arrives late, and the duo prepares to fight to the finish; the scientist however refuses, claiming the battle would take place on the Mountain of Tears, a volcano. While the battle rages on, the volcano explodes. Astro quickly tries to stop an impeding explosion, but fails: two robots are needed to effectively cover up the volcano itself. Pluto, after watching for a while, eventually helps Astro, implying that he has learnt to value of human life. The threat is stopped, however, the scientist reveals his secret invention, a superobot named Bora with 2 million horsepower. Pluto, realises that defeat is unavoidable, asks Uran not to forget him and then sacrifices himself. Bora and Pluto are then involved in an explosion, while Pluto is destroyed Bora emerges unharmed. Astro fights Bora by tearing the robot apart. Afterward, it is revealed that the scientist isn't human (much to the surprise of the Sultan) but his former robot servant, which built Pluto and Bora to show that horsepower isn't the only way to win a battle. He was killed by Bora, the only robot with more horsepower then him.

2003 series
In the 2003 series, Pluto is shown to be the primary antagonist in the episodes The Rise of Pluto and The Fall of Acheron. Built by Shadow (a robot which is in turn built by Dr. Tenma) in order to help Astro evolve, he is shown to be often careless and heartless, with the sole thought of defeating his enemies and fulfilling his purpose (similar in a way to the 1980s series), and because of this does not display any sorrow or emotion to those who he has defeated.

Pluto's method of attacking is a set of homing missiles located in his chest (unlike the horns he used in the 1980s series) as well as some other tactics (depending on the robot he is facing). Every time during battle he is nearly destroyed, however always foils his opponent's method after discovering a "weakness" or a potential flaw that he could use to his advantage. He is also given the ability to analyse and detect these flaws.

Eventually, he develops emotions and a sense of kindness, shown when he sacrificed himself in order to stop Acheron, a robot duplicate of himself, from harming Astro and Zoran(whom he shares a relationship with). He was later rebuilt during the robot war near the end of the series, where he was one of Astro's allies.

The Pluto episodes are actually a 2003 remake of The Greatest Robot in the World story arc, and Pluto is actually the 2003 version of the character Bruton in the 1980s series. Because of this, the characters Pluto fight are also remakes (e.g. Epsilon is actually Photar), although the final character that defeats him is different (he was defeated by Acheron in the 2003 series, Bora in the 1980s). His purpose also differs dramatically from the two series.

Built by Shadow for the same purpose, he was made for Astro to "evolve".

He defeated the following robots:
 * Harley, a rocket ball player robot.
 * Hercules, a Greek gladiator robot.
 * Epsilon, an Australian female robot.

In both series he was shown to have a soft spot for uran.

Manga
Urasawa's Pluto is significantly darker as he is seemingly capable of murdering humans and robots, and is extremely powerful, possessing some control over the weather by generating fierce tornadoes. He goes on to kill the entire "Bora Investigation Squad", always leaving behind a corpse with horn-like protrusions next to it.

Despite this, "Pluto" is actually Sahad, a peaceful, quaint, robot with a strong affinity towards nature and who wished to fill his desolated country of Persia full of flowers. He was created by the Persian Minister of Science, Dr. Abullah. Devastated by the 39th Middle-East War, with his country left in shambles and his family dead, Abullah came to harbor an intense hatred and vowed revenge. He died during the war as a result of a bombing, but before dying, he left the genius Japanese scientist, Dr. Tenma (creator of Atom, the story's version of Astro Boy), with a chip containing part of his brain, and full of Abullah's hatred towards the world. Tenma used the chip to awaken the perfect AI he and Abullah had been working on (due to being programmed with 6 billion personalities, the robot would take an infinite amount of time to simulate all the possibilities and would never awaken; Tenma had theorized that this could be overcome by programming intense, polarizing emotions into it, such as hatred, rage, and despair). The robot awoke, and despite believing itself to be Abullah, it also created a second personality, "Goji".

"Abullah" proceeded to create Pluto, and inserted Sahad's AI into the robot. Goji went on to create "Bora", another, much bigger robot, which was left underground; his plan was to insert his AI into Bora, and tunnel underground, causing a massive eruption that would destroy the planet.

Atom, who had been left in a similar state to that of Tenma's perfect AI due to an attack by Pluto, is reawakened by Tenma, who inserts a chip containing Gesicht (the main character)'s hatred and a recording of his moment of death (as he was defeated and then destroyed by Pluto). Initially he behaves oddly, but after some time, seemingly reverts back to his former self. After learning the whole truth of Gesicht's case, he heads to the source of the cataclysm in hopes of stopping it. He comes face to face with Pluto, who attacks him. At first, Atom is overcome by Gesicht's hatred and attempts to destroy Pluto, citing all the robots he'd killed did not want or deserve death, and rips off Pluto's horns and one of his arms in the process. However, he then hears Gesicht's last words in his mind: "Nothing comes from hatred". Suddenly full of understanding, Atom and Pluto cease their attack on another and proceed to lie down for a few moments. Soon afterwards, Atom goes to disarm Bora, with Pluto (whom Astro has begun referring to as Sahad) at his side. Bora attempts to dissuade Sahad, who rejects him, stating that his father has long been dead, and the AI controlling Bora is nothing more than a fake. He ends up sacrificing himself, saving Atom and the world from the disaster in the process.