xxxHOLiC

Type: Manga
Volumes: Unknown
Chapters: Unknown
Status: Publishing
Published: Feb 24, 2003 to ?
Genres: Comedy, Mystery, Drama, Magic, Supernatural
Authors: CLAMP (Story & Art), Ohkawa, Nanase (Story)
Serialization: Bessatsu Shounen Magazine

XXXHolic is a supernatural/comedy themed manga/anime that is apart of the CLAMP series. It is one of the more popular of the CLAMP series and often shows other CLAMP series being mentioned (ex. Chobits, Sakura Chronicles).

It revolves around a boy named Watanuki and how he stumbled upon a shop owned by a woman named Yuuko. Yuuko's power is to grant wishes, but she can only do so with proper payment. Since Watanuki has seen spirits ever since he was born, Yuuko offers to take away his sight of the spirits in exchange for him working at the shop. He agrees and works at the shop until his debt is repaid.
(Source: xxxHolic Wikia)