Guin Saga  

The Guin Saga, グイン・サーガ

The ancient kingdom of Parro has been invaded by the armies of Mongaul, and its king and queen have been slain. But the "twin pearls of Parro," the princess Rinda and the prince Remus, escape using a strange device hidden in the palace. Lost in the Forest of Rood, they are rescued from Mongaul soldiers by a strange leopard-headed man named Guin, who has no memories except for the word "Aurra."(Source: ANN)

Guin Saga is the longest continuing single-writers work in the world with total circulation exceeding 28 million worldwide. The series has inspired many other Japanese fantasy works such as Kentarou Miuras Berserk or Aquaplus Utawarerumono.Following her diagnosis with pancreatic cancer in 2007, Kaoru Kurimoto continued work on the series up until May 23, 2009 when she became too ill to write. She died on May 26. In November 2013, series resumed publication, with authors Yuu Godai and Yume Yohino alternating between penning the new volumes.Vertical Inc. published the first five volumes of the series in English from June 1, 2003 to May 13, 2008.