xxxHolic is an anime adaptation of a manga series written by Clamp.
It was developed by Production I.G and directed by Tsutomu Mizushima.
[1] The season aired on Tokyo Broadcasting System on April 6, 2006, in Japan and ended on September 28, 2006, with 24 episodes in total.
[2][3] The first season was licensed by Funimation Entertainment in July 2007.
The ending themes are "Reason" by Fonogenico for the first thirteen episodes and "Kagerou" (蜉蝣, Kagerō) by Buck-Tick for the following ones.