Cryonis is one of the more underrated runes in Hyrule Warriors: Age of Calamity. In The Legend of Zelda, Breath of the Wild, it was mainly used to reach new places using ice pillars, and not so much as a form of attack.
Age of Calamity changes that. It's actually quite the effective weapon, but only under the right circumstances. This mission is in Central Hyrule. The game suggests playing once you're level 8 or higher. If you can't locate the level, note it unlocks after you clear the Mipha, The Zora Princess mission.
There are three phases to the mission:
- Defeat 100 Bokoblins
- Capture the outpost
- Defeat a Moblin
The key to this mission is the key to this game in general: gather swarms of enemies for more kills in less attacks.
As you can see, there's a large body of water in the level. When Link uses Cryonis in water, nearby enemies freeze and perish. Make sure there are a large number around you before you activate the Rune.
After you defeat the enemies in the outpost, you must defeat a Moblin. Dodge his attacks and wait until you see a prompt to use the Cryonis Rune, which will make short work of him.
When you complete the mission you get an Ethereal Stone, Chillshrooms, Chillfin Trout, and a weapon.
Here's how to beat the level from start to finish.