Blue: Mayard Duchy Army and Highserk Empire Army
Red: Crest Kingdom Army and Libertoa Trade Federation Army
Yellow: Former provisional border line
Purple: demonic territory
Light orange: Mayard territory
Gray: mountainous region
Light blue: bodies of water

By means of a surprise attack and hidden ambushes, the Crest Kingdom seized control of the provisional border line, then split its army into three large forces and began a full-scale invasion of the lands controlled by the Mayard Duchy. Its main force sealed off the six passes of Zerebes, successfully cutting the lines of communication connecting the peninsula to the outside. The remaining two armies concentrated on pinning down the duchy garrison forces stationed at Sarajevo and Refun, both of which possessed sizable troop numbers, and carried out blocking actions to prevent their movement and junction.

Outnumbered and having lost the initiative, the Mayard Duchy army and the Highserk Empire expeditionary force judged that a counterattack at this stage was impossible. While establishing a defensive line along the outer perimeter of the Zerebes mountains, they used delay tactics with their ready standing army in order to withdraw the surviving troops and civilians fleeing from the border region into Selta.

A counteroffensive against the exposed edges of the enemy encirclement was also considered against the Crest Kingdom army, whose forces had been divided by the blockade of the six passes of Zerebes. However, due to insufficient troop strength and intelligence, as well as the danger of being lured into a trap, any aggressive mobile defense was abandoned.

The Mayard Duchy intends to shatter the enemy offensive along the outer defensive line of the Zerebes mountains, buy time, await reinforcements from Highserk Empire, and then engage in a decisive battle. On the other hand, the Crest Kingdom, having secured firm initiative through its pre-emptive strike and division of enemy forces, aims to force Mayard into submission while preparing several options: a direct assault on Selta, a decisive field battle, or a prolonged campaign using siege fortifications.

Mayard Duchy army and Highserk Empire army
Selta Peninsula sector: 13,000 men
Sarajevo sector: 2,000 men
Refun sector: 4,000 men

Crest Kingdom army and Libertoa Trade Federation army
Selta Peninsula sector: 34,000 men
Sarajevo sector: 4,000 men
Refun sector: 4,000 men