Zetas is one of those things that you are behind on for years and then you end up sitting on a pile of hundreds of zetas, just waiting for the next character to join the roster so you can spam click through all ability upgrades until you get to omicrons. I myself have been behind on zetas since I started the game. I am finally (slowly) approaching a maxed out zeta roster. I've got about 30 left to apply (excluding Era units) and half of them are those awful zetas that no one would apply unless they have materials to spare.
Capital Games Team
