Graizel Prison is a location originating from the Fire Emblem: Hasha no Tsurugi manga. It appears in the chapter of the same name in first volume of the manga. It is situated on the western end of the mountains seperating Lycia and Bern.
Hasha no Tsurugi
Graizel Prison is a stronghold surrounded by cliffs from all sides save for the front. Having such natural defense of the invaders are left with few options of approach. It is this fact that leads Warren to deam infultration to be a suicide mission and refuse to aid Gant in his quest to save their princess Tiena who is set to be executed at the prison. Despite Warran's protests and warnings, Gant and Al still choose attempt to save the Tiena on their own, though they are eventually discovered and completely surronded by the prison guards. It is only with the help of Warran, now with new resolve, charging in from the rear cliff with all of his men that Gant and Al are able to save Tiena.
The Binding Blade
While Graizel Prison does not make an appearance in the games story in any capacity, a trial map based on it was added to 50 Fire Emblem: The Binding Blade game cartridges as a part of a special contest based on Hasha no Tsurugi in the V-Jump magazine.