Mukotsu is the fat poisoner from the Band of Seven, a group of mercenaries who's bloodthirsty tactics were so feared that a cadre of regional rulers trapped them in the mountains and had them executed. Naraku uses his Shikon shards to revive the men, who go on a killing spree searching for more shards.
Mukotsu is the most repulsive member of the Band of Seven. He uses gasses, acids and poisons of all varieties to kill his opponents and takes great pride in extending his victims' suffering as long as possible. Mukotsu carries a large sack that is full of the ingredients he uses to create his toxins. He also uses oversized bamboo chutes as makeshift cannons to disperse his poisons. Upon his arrival he interrupts a battle between Inuyasha and Jakotsu using a poisonous mist as a way of saying "hello" to his old comrade in arms. Mukotsu is instantly attracted to Kagome and uses his expertise to capture her and seperate her from Miroku and Sango.
With Kagome paralyzed from the poison, Mukotsu attempts to seduce the girl, revealing himself as a deranged individual who views himself as handsome and attractive. When Kagome gathers enough strength to fend off his advances, Mukotsu's personality suddenly shifts as his eyes well with tears. With his illusion of himself shattered, Mukotsu forces himself on Kagome and prepares to rape her, admitting that she is just like every other woman he has encountered in his sadistic travels. Shippo manages to escape and tries to get word to Inuyasha that they are all in trouble. Luckily Sesshomaru happens to arrive and makes short work out of Mukotsu. He kills him in one quick blow by cutting him in two.
The Meaning Behind the Name
"Mu" is written with the kanji meaning "mist". The "kotsu" character is "skeleton" or "remains". Each of the Band of Seven have the latter character in their names, which relates to the fact that they are actually undead.
Tetsu Inada & Trevor Devall
Tetsu Inada is the voice behind Mukotsu. He also provided another Inuyasha voice for Manten. He is also Mr. 1 in One-Piece and Harry Ord in Turn A Gundam.
Trevor Devall plays the role of Mukotsu in English. His other roles include Shesta in The Vision of Escaflowne, Ryukotsusei in Inuyasha, Mu La Flaga in Mobile Suit Gundam Seed, and Shiro Mibu in The SoulTaker.