Aground

There are two ways to get this. 1. Boss Fight - kill the 2 mirrows which will require lots of food and ideally the shotgun w/ plenty of ammo.

2. Or by completing "Convince the Mirrows" quest.

How To Start
This quest is an alternative to the boss fight in Confront Mirrows. During the quest, you have the option to run away from the scientists and speak to the Mechanic. After finding the secret lab in the Space Ship and reading the terminals, she will give you this quest.
The ??? in the quest log is Dragon Armor. To produce this, you must complete the quest Wyrm Research on the Eastern (Magic) Island. You will then need to use an Alter Gem to transform an Adult Dragon into the armor.
Speak with the Mechanic after obtaining the armor. After a cutscene, the quest is complete. Completing this quest will also fulfill the requirements for Confront Mirrows, so you can return to the Inn to complete it.

Sharing info from a guide I found on this, credit for this guide info goes to "Burj" on this site: https://www.ezpz.gg/aground/convince-mirrows