Legato Bluesummers

Voiced by: Toshihiko Seki (Japanese), Richard Cansino (English)
Legato Bluesummers (レガート・ブルーサマーズ, Regāto Burūsamāzu) is a man who devotes himself to Knives, and makes it his main goal to have Vash experience eternal pain and suffering. He serves directly under Knives, which also gives him command of the Gung-Ho Guns. He is originally a sex slave who Knives accidentally saves while wiping out the town. Legato pledges to serve Knives, who gives him his name. During his time as a slave, he weaves thousands of special metal threads into his medulla oblongata. They are dispensed out of a skull-shaped emblem attached to his left arm. When released, the threads transmit electricity to control his victim's muscles over. The threads themselves are only a few molecules thick and able to take over an entire town with ease.

Legato takes over while Knives is injured, and uses the Gung-Ho Guns to play a "game" with Vash. He gives Vash a case and each Gun a half coin to place into it, stating that "something interesting will happen" after it is completed. After Knives recovers, Legato's body is crushed and his neck twisted for using the Guns for his personal agenda. Legato is consequently restricted to a coffin-like container, which is carried by an ogre. Legato later gains a new coffin with metal appendages that allows limited movement. He eventually learns to use his threads to manipulate his own body, and takes up a ball and chain weapon and a handgun. He later fights Vash with the case activated, which nullifies his threads, and loses. He forces Vash to kill him after using hostages.

The anime places Legato as the leader of the Gung-Ho Guns, recruited by Knives to make Vash's life a living hell. Knives gives Legato Vash's left arm, which grants him the ability to manipulate victims with telepathy. He sees Knives as a god and, like Knives, sees humans, even himself, as trash to be exterminated. Legato forces Vash to kill him by using his powers to threaten Milly and Meryl. Legato thus becomes the first person that Vash ever consciously and willfully kills, fulfilling his promise to "make Vash the Stampede suffer eternal pain".

Source: Wikipedia