The D.Gray-man anime and manga series features a diverse cast of characters created by Katsura Hoshino. The series is set on a fictional Earth at the end of a nineteenth century where the Black Order wages war against the Millennium Earl who intends to destroy humanity with his army of Akuma, weapons created from the souls of the deceased when their loved ones curse God for their loss. To aid in their efforts, the Black Order scours the world for the 109 pieces of a divine substance called Innocence, which has been washed away during the Great Flood, and for people who can use anti-Akuma weapons, the Innocence in its weaponized form. These people, called Exorcists, are able to effectively fight against and destroy the Akuma. One Innocence, referred to as the "Great Heart" will assure their victory. However, the Earl is also looking for the Innocence and the Heart with the intent to destroy them.
The main character of the series is Allen Walker, a young Exorcist who recently joined the Black Order after training with his master General Cross Marian. When presenting himself to the organization, he is mistaken for an enemy and is attacked by another Exorcist, Yu Kanda. However, once the mistake is realized, Lenalee Lee prevents any Kanda from causing further mishap. Once inside the headquarters, Allen learns he is the prophesied "Destroyer of Time" who is the only one who can defeat the Millennium Earl. As the series progresses, Allen meets many of the members of the Black Order headquarters as well as those in other branches worldwide. He eventually meets a young, aspiring bookman called Lavi and his predecessor Bookman, who follow Allen on his adventures to witness and record the events for the bookman's record. Allen also encounters the antagonist the Millennium Earl, his Akuma army, and the Noah Family, a group of humans who aid the Earl in his plot to destroy humanity.
Yu Kanda (神田 ユウ, Kanda Yū) is a cold and rude 18-year-old Exorcist from Japan. He is the first Exorcist that Allen meets at the Black Order HQ and since then they have an ongoing loathing toward each other which often causes them declare a series of insults and offensive statements towards each other. He is a disciple of General Tiedoll and hates the way the man treats him. He hates a lot of things which cannot be listed and few of them are naive people (Allen) and people who breaks their promises (Allen in chapter 15). Only General Tiedoll and Lavi calls him by his first name. He and Lenalee knew each other when they were young and was the only person that can comfort Lenalee without asking her anything whenever Malcolm C. Leverrier appeared to the Order.
Later, in recent chapters , Kanda is a Second Exorcist, a type of Exorcist created in the Synthetic Disciple Project Central forced onto the Chan and Epstein families nine years ago. Because of this, he can see lotus flowers blooming wherever he goes. As a child, there was only one and he was told it was an illusion. Since then, the flowers have multiplied. He can recover much faster than ordinary humans due to a mysterious tattoo above his heart. Kanda refuses to die until he finds "a certain person".
Originally forged by Zhu Chan, his anti-akuma weapon Mugen (六幻, Six Illusions) is an Innocence that originally took the form of a sleek chokuto and is later reforged as a katana. Mugen is capable of unleashing several techniques dubbed "illusions". However, his third technique draws his life in order for him to gain power (in chapter 93). He is voiced by Takahiro Sakurai.
Later in the story, Kanda's mysterious origins are discovered when the Noah of wisdom, Waizuri shows Allen, Road, another Second Exorcist named Alma who's in a coma, and Kanda are shown Kanda's memories. Allen gets angry at Kanda, so he punches him in the forehead. However, Alma awakens and it's discovered that he and Kanda were forced to fight when Alma, who had been his best friend, went berserk. Alma had killed about 40 people in his rampage. Kanda activates 6th illusion, but stabs Allen. Allen begins to transform into a Noah, but stops as his cursed eye activates. Allen discovers that Alma had been the woman Kanda loved in his previous life. Alma begs Allen not to tell Kanda,or "he'll give up on life". Kanda and Alma go to the area of Allen's first mission, and Alma tells Kanda that she loves him. A ripple is shown in the lake of lotuses and Kanda tells Alma,"I know."