Robin Sena is a "craft user", born in Japan and raised by the Roman Catholic Church in Italy.

The series begins when Robin arrives in Japan from Italy to gain information for Solomon headquarters about a fabled item that holds the "secrets of the craft," while acting undercover as a new hunter to the STN-J in their efforts to stop and capture witches.

STN-J's hunters carry small vials of it on necklaces in the shape of a cross as a form of protection against their targets' craft.

The TV series was produced by Sunrise and Bandai Visual and directed by Shūkō Murase, with Aya Yoshinaga serving the role of chief writer, Kumiko Takahashi designing the characters and Taku Iwasaki composing the music.

In October 2003, it debuted at the 3rd Annual Metreon Festival of Anime in San Francisco, followed by a Q&A and autograph session from Kari Wahlgren, who provided the voice for the title character.

[10] On April 5, 2004, the SciFi Channel released a press release stating a listing of new series and films in development for the future, one of which was a live action version of Witch Hunter Robin produced by Roy Lee and Doug Davison, who were credited as the producers for the movie The Ring.

Bamboo Dong, a columnist from the website, has stated that she cannot make enough positive comments about the series and that it is "a show that everyone must absolutely see".

However, she comments that the ending moved a little too fast and spent much of its time with plot revelations, missing its chance to give the series "that extra kick".

[14] Carlo Santos praised the series, saying that it was a unique tale that was gorgeous and engrossing to watch and one of 2004's best adventure anime.

And concluded his review with "In short, Witch Hunter Robin is this fall's anime bright spot (despite being almost entirely black and gray).

This is a mature, evenly paced supernatural thriller, chock full of mystery, intrigue, and a few exciting battles for good measure.

[17] Jason Bustard from THEM Anime Reviews comments that the supernatural and spooky undercurrent in the setting would fit perfectly into The X-Files or Millennium television series.

In contrast to the review from Anime News Network, Bustard believed that the story moved at a brisk pace.

The series' setting was said to be "a fairly severe, almost oppressive gothic design" and that the color palette and the plot's focus on the occult contributed to the dark feel.