Arkantos and his allies must close a portal to the Underworld, preventing the Titans from entering the mortal realm. This mission often involves defending a key location against waves of powerful enemies, including Myth Units and potentially a Titan. You'll likely start with a fortified position and need to reinforce it. Your primary objective is to hold the line and prevent the enemy from destroying a specific structure or reaching a certain point on the map.
Focus on building a strong defensive perimeter with walls, towers, and fortresses. Train a diverse army, including units strong against Myth Units (heroes, specific human units) and units strong against human units. Research all defensive and military upgrades. Use God Powers that can deal area damage or provide strong defensive buffs. 'Frost' or 'Restoration' can be invaluable. You'll need to manage your resources carefully to continuously replace lost units. Consider building multiple production buildings to ensure a steady stream of reinforcements. This mission is a test of your defensive capabilities and ability to withstand sustained assaults. Prioritize destroying enemy siege units that target your defensive structures.