The Gustaberg Front is a theater of the Crystal War in Final Fantasy XI: Wings of the Goddess. It includes the southernmost territories of Quon, where the Republic of Bastok risks being overrun by the Quadav Shieldwarriors.
Bastok Markets is the heart of the Republic's war effort. With the port lost to Sahagin and the mining district pressured by its proximity to Antica and Quadav-infested tunnels, the markets are the nation's last line of defense. They have been heavily reinforced for this purpose and form a barrier around the metalworks, where the government resides.
North Gustaberg is a large valley found northwest of Bastok and south of Grauberg. A mountainous cliff divides Gustaberg in half and a ramp carved into its face is the only means of passing from one side to the other. Water cascading over this boundary, though undrinkable due to mineral contamination, forms a dramatic natural wonder, the Drachenfall, which feeds Zeikt Creek as it flows west into Dangruf Wadi.
Encroaching Quadavs and Goblins make travel through Gustaberg dangerous even in absence of enemy troop movements. A Cavernous Maw connects the valley to itself twenty years in the future, however, providing an escape to less threatening times.
Invincible Shield, a famed Galka warrior, leads the Republican Army's 3rd Division in Gustaberg's defense. In turn, the Quadav Shieldwarriors assigned Do'Bho Venomtail and the Dadough Vanguard to seize control of this area. Do'Bho's mastery over poison magic is unparalleled.
Grauberg is a network of hills and vales lying south of the Pashhow Marshlands. It became a vital supply route for the Alliance of Altana after the western roads through the Konschtat Highlands were lost as a result of the Battle of La Theine. It is home to exotic creatures such as Pixies and Wyverns. A fair Elvaan maiden named Areuhat is known to wander the area with no apparent fear of its dangerous inhabitants.
Bastok's military efforts in Grauberg are headed by the 2nd Legion Scouts under the command of Adelheid Sturm, a Hume scholar. She notably invented a range of status-inducing Tubes that detonate in the presence of enemy infantry and deploys these on the battlefield to confound the Beastmen. In turn, the Quadav Shieldwarriors assigned No'Mho Crimsonarmor and his elite guard to seize control of this area. No'Mho bombards the opposition with divine magic.
An alternative version of this region exists in Abyssea. It is accessed via the Cavernous Maw located in North Gustaberg.
The Ruhotz Silvermines are an vast array of excavated tunnels stretching between Gustaberg and Rolanberry Fields far to the north. They were once a profitable enterprise for the Republic but were adopted as a supply route by the Quadav. Bastok has consequently attempted to secure the mines and they remain a volatile channel for subterfuge from either side.