

王国の鍵
After the king and his eldest son die, the kingdom of Landor is left without a ruler. Asta, the last surviving member of the royal family, stands in line for the throne. However, before he can claim it, he must fulfill a quest: find the legendary "Key to the Kingdom". Both ancient beasts and a variety of contenders, including a princess, a dimwitted military captain, and a villainous aristocrat, imperil his journey. Someone will find the Key, but will it be Asta? (Source: CMX)
Oukoku no Kagi was published in English as The Key to the Kingdom by CMX Manga from September 19, 2007 to December 30, 2008.
The Key to the Kingdom has 29 chapters.
The Key to the Kingdom has 6 volumes.
The Key to the Kingdom is currently finished.
The Key to the Kingdom was written by Kyouko Shitou.
The Key to the Kingdom was published Aug 2002 to Nov 2004.
Ranked higher than 25% of all manga on AniTome (out of 30,039)