Astria Ascending

I can't recal exactly when the Cosmo Break feature unlocks in the story, but once it does it's quite simple. It works similar to Limit Breaks in Final Fantasy, though the blue bar under your character will only advance if you do what applies to their specific roles. Eko needs to heal, Zimar needs to use spells, etc. Once the blue bar is complete filled, press  while hovering over the character's basic attack prompt to then launch their Cosmo Break.