First things first, you'll have to capture a Galarian Yamask on Route 6 in Pokemon Sword and Shield. It should appear in the overworld quite commonly. 展开

There are two things you can do to evolve Yamask:
•Make it Take 49 Damage
•Bring Yamask beneath a certain stone arch in the Wild … 展开

Yamask in hand, you'll have to do something sort of terrible to it to begin the evolution method into Runerigus. Take Yamask into battle, and let it take at least 49 Damage. Thi… 展开

Now that you have a barely-alive Galarian Yamas, take it to the Dusty Bowl in the Wild Area Travel beneath the largest stone arch here. As soon as you go beneath the arch, Yamask should … 展开