Sung-Guan makes an appearance in the pages of ‘Takuan from Koto’ only towards the end of the second book, ‘Hunters of Weredemons.’ Let’s not discuss how it happened, but Sung-Guan became the victim of an unlucky sorcerer named Bricabrac, who, perhaps for the only time, found himself blessed with good fortune.

As a result, Sung-Guan acquired a long and clingy tail, as well as golden fur, resembling a mountain monkey. Along with the tail, Sung-Guan also gained the boundless energy of the celestial marten Ta-Guan, which, of course, inhabited the one who later received the name Sung-Guan.

If you want to learn a little more about Sung-Guan, you must read Makipedia.