In this world... The great military power Dearumor boasts an almighty force. Land is cleared, new weapons are developed, conventional strategy and tactics are perfected into an art which culminates on the well trained officers and soldiers, and surrounding countries are conquered. Everyone believes that no one can stop their charge, no one doubted that the world is for Dearumor to take. But, there are three powers that can actually oppose them.
First is the Fettercairn Treaty Alliance, led by the Ruciun Kindom. Seeing Dearumor's actions as unforgivable, the alliance that's formed in self-defense is capable of fighting equally the invincible Dearumor military whether at land or sea.
Another are the sea creatures that are living deep in uncharted waters, the Last Kin. Dearumor's navy which unwittingly trodden on their proud waters, got annihilated.
And last... are those that are freely rampaging on the high seas, the pirates.