Is this xmas event really the only time in the near future we're given the option to purchase this mat? I'm trying to plan ahead for Arthur in Februaryish and I'm not immediately seeing them as drops or shop items which super sucks as I need hundreds of them and 60% Okeanos is awful tbh...
They're not meant to be easy to obtain. Just easier than some other mats.
Eventually, we're supposed to get a system where instead of getting a bronze mat on login bonuses, we get a ticket that can be exchanged for certain materials. That should make things at least slightly easier.
https://grandorder.wiki/Proof_of_Hero
there is a lot of event will provide proof of hero. Sadly, indeed until next summer, there is no quite event will have that in shop.
You can try Dallas (or Lubbock) of E Pluribus Unum for free quest farming. Although still ~25 apd is not better than Okeanos.
