Where to get Mystic Mastery cores?

Hi I am trying to get Mystic Mastery cores for Mystic Depression and does anyone know where I can get them?

Comments

Loyalty store. They rotate in occasionally. Or you can spend units in the mastery store. They appear in both stores at the same time.

I just checked and I didn't see any

They rotate. Currently it’s the tech cores I believe. You just have to wait and check everyday.

Loyalty store. It rotates between classes

Thx