Kansuke

"Burn in hell Onigumo!"

Rasetsu (羅刹) was a bandit leader fifty years before the start of the series during the original tragedy of the Shikon Jewel which ended in the death of Kikyō, the sealing of Inuyasha and the birth of Naraku.

History
Rasetsu, who was originally known as Kansuke, lead a group of bandit thugs which included a man named Onigumo. After being tricked by Onigumo into attacking the priestess Kikyō in an attempt to acquire the Shikon no Tama, which ended in Rasetsu's defeat at the hands of Inuyasha and the loss of his right eye, Rasetsu sought to make the man who had tricked him and stolen his men pay. As Onigumo and the rest of the bandits who declared him their new leader celebrated at a local inn, Rasetsu planted a bomb which exploded leaving Onigumo severely injured, all of his body was badly burned except for the spider shaped scar that was already on his back. To finish the betrayer off the men threw him off a cliff. This act, unfortunately set the plot of the entire series in motion, making Rasetsu the sole perpetrator of not only the creation of Naraku, but the shattering of the Shikon Jewel.

During the story
Fifty years later Rasetsu, now an old man, met the revived Kikyō not realizing that she was the same Kikyō he had tried to kill decades earlier. The man is later attacked and killed by demons but before he draws his final breath, Rasetsu asks Kikyō to take a lock of his hair to the sacred Mount Hakurei. Naraku had filled his heads with thoughts that he would be properly saved if his remains were taken to Mount Hakurei. But instead it was Naraku's plan to lure Kikyō there so he could test out if he could kill Kikyō and that Onigumo's heart would not stop that.

Manga vs. Anime

 * Unlike the anime version of Rasetsu, in the manga he was an old and weak bandit without mentioning his name. During his first appearance of manga, he managed to stop a travelling priestess, Kikyō, who was passing by and told that he could feel Kikyō's divine powers. While holding his last breath, he cut off his hair and gave to Kikyō as an, hoping that she would accomplish his request by sending the hair to Mount Hakurei for expiate purpose.
 * Apart from the difference of his history, in the anime Rasetsu wears eye-patch on his right eye, but in the manga he wears nothing. Moreover he doesn't wield any Shikon shards.