Legato was originally a sex slave, and was used by a town of over 1300 people. He developed his technique to control others during the time he was held captive. He could have used it to kill all of them but he didn't as he saw no purpose behind it. One of the people found out about his abilities and decided to punish him. Unfortunately for that fellow and the entire town, Knives came along and killed them all, chopping them into pieces in an instant. Legato then joins him in his quest to destroy the human race.
During the July incident, when Knives is found lying on the ground in a pool of his own blood, Legato begins to cry. The doctor that was with him tries to reason with him, but he couldn't be reached, until Knives gets things straightened out.
Major Story Arcs
The first meeting between Vash the Stampede and Legato was in a small town, Vash was standing on a bench after receiving a football in the face. In order to repay the kids that gave him a shot to the face, Vash treated them all to ice cream. Unfortunately a girl nearby that Vash wanted to treat refused him, but took a hot dog that Legato gave her without hesitation. After a telepathic discussion the two had about Millions Knives, Vashs' brother and about the Gung Ho Guns, Legato left but not without giving Vash a little gift: the head of a shoemaker that Vash had visited earlier that day. Later that day he met with Monev the Gale to ensure that he would be ready to face Vash soon.
The Meaning of Life is Death
After witnessing E.G. Mine's defeat at the hands of Vash and getting a few threats from him, as to Legato being the one who was going to hunted down from now on, Legato left the town. Soon he would have what seemed to be a lunch in a small bar, but his lunch would be interrupted by a small gang, led by the Roderick the Slaver. Legato unwillingly caught the attention of their girls, girls that were taken from their families. One of the gang members tried to scare off Legato with a few shots. Not very impressed but a little angered by his attitude, Legato showed him what true power was all about. This was the first time Legato used his powers in the manga. He controlled the attacker's left hand, using it to have him pull out his heart. After seeing this, the rest of the gang tried in vain to kill Legato, but ended up being forced to kill each other. He left then after he gave a little speech on the meanings of life to the gang's female slaves.
Reuniting the Gung Ho Guns
After killing the leader of the Roderick gang, Legato seemed to be pursued by the band of outlaws, but unfortunately for them, the Gung Ho Guns were throwing a party and they were going to use the bodies of the band to prove to them their awesome powers. Legato ordered the Gung Ho Guns to kill only half of the band. About 50 people were taken down by what seemed to be 7 members of the team, the other half had the job of making "good use" of the dead bodies, as Legato called it. In the mean time Nicholas D. Wolfwood was meeting Vash.
After Dominique's failure with Vash, Legato and the members of the Gung Ho Guns that killed Roderick's gang met up with the doctor that was treating Knives. Chapel (Nicholas D Wolfwood) also decided to join the party. He was a little late but he wasn't late for the party that was held in a church. The "resurrection" of Knives was a very painful one, as Vash who was unconscious at the time, woke up and started screaming of Knives' return. Awakened and wounded after his previous battle, he rushed to the church on the mountain, only to find a crippled Legato at the hands of Knives. The reason was a simple one: Legato was supposed to make Vash suffer, and not try to kill him, and so he had tried to use the Gung Ho Guns for his own purposes. A few minutes later Knives made his move on Vash, using his superior speed, in mere seconds Knives left Legato, grabbed Vash, and nearly wound up destroying them all using Vash's angel arm. Luckily Vash manged to move his arm, the ray of energy instead hitting the moon in the sky above them, leaving a huge crater in it.
Two years later after he was crippled by Knives as punishment, Legato is seen with one of Leonof's puppets who was giving him the news of Vash resurfacing. Legato made an appearance along with a few other Gung Ho Guns members, when they used their powers to crush a sheriff task force. After Legato used his powers to get them in line, he made them go in a container, forcing the men to crush their own bodies together in it. He then received some more information on Vash's whereabouts.
After this Legato decided to have a bite to eat, as he began eating, he invited the other Gung Ho Guns to step forward: Gray the Ninelives, Midvalley the Hornfreak, Hoppered the Gauntlet, Zazie the Beast, Rai-Dei the Blade, and Leonof the Puppet-Master. During the time he was eating, Midvalley decided to lecture Legato on how they, the Gung Ho Guns should be stopping people like Vash and Knives, instead of helping them. So Midvalley decided to point a gun at Legato, a very big mistake, as Legato used his powers and nearly broke Midvalley in half. He then explained to the Gung Ho Guns their new objective: they were no longer to kill Vash, but to make him suffer instead, to show him the true nature of humanity. He also noticed the betrayal of Wolfwood, when he later fought against Gray the Ninelives.
Bottom of the Dark
Legato is seen later after the two battles between Vash and Wolfwood against Midvalley and Hoppered had ended. He steps in to find Midvalley and Wolfwood as they were trying to kill each other. When Midvalley sees Legato, he tries to kill him, but fails due to the fact that Legato forces Hoppered to shoot Midvalley, killing him almost instantly. He then uses the massive motorbike his new body was driving, and crushes Midvalley's bodu underneath it, killing him. He then tries to to attack a transforming Vash, but Wolfwood and Hoppered try to stop him. Then Zazie steps in, using a new body, this time the body of a young girl. Legato is then shot by Meryl and Hoppered, while Hoppered and Wolfwood are shot by Zazie. A scared Legato then tries to finish Hoppered off, by using the dead body of Midvalley to shoot him. Legato goes berserk and tries to kill everyone but Elendira the Crimsonnail steps in and uses his spikes to stop Legato, and then drags him back to Knives.
The Gung Ho Guns were nearly wiped out after their last confrontation with Vash and Wolfwood, so Legato had a little chat with Elendira about the future of the Gung Ho Guns. Legato told Elendira that he had invited two members of the Eye of Michael organization to be part of the Gung Ho Guns, their names being Livio the Double Fang and Chapel the Evergreen. The two new member came eventually, but they didn't come empty-handed, as Livio brought the bodies of two intruders that had been trying to get in. Moments later he, Livio, Chapel, and Elendira witnessed Knives's ability to absorb other plants like himself.
Legato is later seen trying to talk Elendira into stopping the battle between Knives and Vash, but Elendira doesn't listen, so he goes into the middle of the battle and stops Knives from absorbing Vash, saving his life in the process. Knives then gives the order that Legato is to keep an eye on Vash. Legato left with Knives, Vash and Elendira on the original SEEDS ship that settled their planet. He and Knives tortured Vash along the way, reminding him why he should hate humans. Legato was very cautious around Vash.
Legato is soon attacked by Wolfwood in an attempt to save Vash. It seems that Legato had been using his powers the past half a year to bring down Vash, whose powers were now at their weakest. Legato gets shot in the back though by Wolfwood before he can finish, but he still manages to make Wolfwood shoot himself.
Legato was on his deathbed after getting shot again. When Zazie tries to take Knives' body though, Legato stops him, and attempts to kill Zazie's body with a gunshot, but he fails, and so forces Zazie to drive her own arm through her body. Zazie's body is later fully destroyed by Knives. Legato manages to save himself from his deathbed by using the metallic threads he normally uses to control other people's bodies, thereby also allowing him to overcome his body's crippled condition. During the battle between Knives and Vash, Legato jumps in and confronts Vash. Legato defeats Vash, but only momentarily. As Vash gets back up, seeing himself in Vash's actions, Legato takes the coin box he'd given him, and tells him that it is a miniature magnetic field generator, activated by the coins taken from defeated Gung Ho Gun members, and that it was going to be used to disable Legato's powers.
Even without his powers, Legato was still a formidable opponent for Vash. He had incredible speed, and was now using the body of the woman that had carried him around while he was crippled as a wrecking-ball, one that had machine guns on the side. He tries to defeat Vash with it , but he can't and as soon as the wrecking-ball is destroyed, Legato draws a different gun, as the duel had just begun. Knowing that he would be defeated just like Elendira, Legato activates his powers once more, on himself, in order to attack one last time. Legato tells Vash that he was already 8 months under the influence of his powers, and that nothing can escape it. Legato fails however, and knowing that he couldn't control Vash he gives up, and orders Vash to kill him for his failure. Vash refuses but Legato threatens to kill Vash's new ally Livio, who's head he was about to rip off using the body of the dead Elendira, and threatens to do the same to everyone else Vash cared about. Vash is left no other choice, and willingly kills Legato.
Powers & Abilities
The powers of manga Legato are very different from his anime counterpart. He uses a special technique he developed while he was caged, which uses thousands of special metallic threads located in his medulla oblongata, that are released out of a skull-shaped emblem attached to his left arm, when they are released, they attack the muscles of the victim, sending electricity through them that enables Legato to control their body. These threads are a only a few molecules thick, and he can take control an entire city with them; he even used them on himself, allowing him to move his body once more after he was crippled by Knives.
Legato also had a gun with a knife on top and in his final battle with Vash he used the body of the woman that was transporting him while he was crippled as a weapon. Locked within a sort of Iron Maiden, she had spikes, machine guns and even a laser cannon as part of her arsenal.
The Legato in the anime is quite different from his manga version. He is never crippled by Knives, and he is given Vash's left arm which gives him telepathic abilities - while his manga version uses special threads to control people's muscles with the electricity transmitted through them. He is ultimately killed by Vash, when he threatens to kill Milly and Meryl. He is the only person that the anime version of Vash ever killed.