Aegis War

The Aegis War is a cataclysmic war in Xenoblade Chronicles 2. The war involves both Aegises Malos and Mythra, and the main focus of Torna ~ The Golden Country and its legacy plays a role in Xenoblade Chronicles 2.

Cause
The initial spark is when Amalthus brought back two Core Crystals; Malos and Mythra's to Alrest after climbing the World Tree. Back in Indol, he awakens Malos who then lost control of him and proceeds to raise the entire world with his destructive powers. To contest him, Amalthus gave Mythra's Core Crystal to Addam who she awakens as his Driver at Olethro Ruins.

Legacy
Although Malos was defeated and the war ended, it left a huge impact on Alrest; the people began to fear the power of the Aegises. Some nations desire that power while others want to destroy it. Amalthus then bars entry to the World Tree due to the war, and enlisted Ophion to guard it from any intruders.