Kitetsu

Kitetsu (鬼徹) is a swordsmith who crafted the Kitetsu sword series. He has yet to make an appearance in the series, but he has been mentioned in Chapter 97 and Episode 49.

Known Work
Each of Kitetsu's blades, which are all named after him, are cursed, and bring tragedy to whom ever wields them. Roronoa Zoro, who wields the Sandai Kitetsu, seems to be an exception, as his luck surpasses the curse. With each new sword, the classification lowers, seemingly decreasing in quality and strength.
 * Shodai Kitetsu (Saijo O Wazamono Grade Swords)
 * Nidai Kitetsu (O Wazamono Grade Swords)
 * Sandai Kitetsu (Wazamono Grade Swords)

Trivia

 * It seems from their name and classification, the Kitetsu swords were made weaker with each new sword. Being of the highest grade of the three swords, Shodai Kitetsu is the strongest of all the Kitetsu swords. Its name also indicates it was the first of the three to be made. Nidai Kitetsu was the second to be made. It was graded in the Ō Wazamono making it the middle of the three swords in terms of strength. The Sandai Kitetsu is the weakest of all the Kitetsu swords. Its name also indicates it was the last of the three to be made.
 * Kitetsu's name literally means "Demon-Splitter".
 * Kitetsu's knack for making cursed sword that harm it's user seemingly matches the cursed swords created by the japanese swordsmith Sengo Muramasa.