D.Gray-man" is a popular anime series based on the manga of the same name by Katsura Hoshino. The anime adaptation was produced by TMS Entertainment and directed by Osamu Nabeshima. The first season of the anime aired from October 2006 to September 2008, with a total of 103 episodes.

The story is set in a fictional world where humanity is threatened by demonic beings called Akuma. The main character is a young exorcist named Allen Walker, who has the ability to control a powerful weapon called Innocence. Together with his fellow exorcists from the Black Order organization, Allen must fight against the Akuma and their leader, the Millennium Earl, in order to save humanity.

The series is known for its unique and complex plot, which includes elements of mystery, horror, and action. The story is also notable for its well-developed characters, who are all given distinct personalities and backstories. The main character, Allen Walker, is particularly memorable for his tragic past and his determination to protect others despite the risks.

The animation quality of the series is also praised by fans, with the fight scenes being especially well-animated and visually impressive. The soundtrack of the anime is also well-regarded, with a mix of orchestral and rock music that adds to the atmosphere of the series.

Despite its popularity, the anime adaptation of "D.Gray-man" has faced several challenges over the years. The second season, which was meant to continue the story, was delayed due to production issues and ultimately aired in 2016 under the title "D.Gray-man Hallow". This season was much shorter than the first, with only 13 episodes, and was criticized by some fans for its rushed pacing and lack of character development.

Despite these criticisms, "D.Gray-man" remains a beloved series among anime fans, with its unique story, memorable characters, and stunning animation making it a standout in the genre.