Quote Originally Posted by Unregistered View Post
Save the cores for when you can turn them in for draconic eye shards. They should be in the reprint version of the exchange.
They should've been in this one too...

Anyway, R Grails aren't worth anything. You save like, ~2600 Gems with each of those. So don't buy those.
I believe you'll need Cores for the Advent level 150 SSR limit breaks in the future, 5 per Advent. So combined with the Dragonic Eyes, you'll need 11 of them per Advent, but you can only earn ~7-9 per event (without lucky double Core drops). That will slowly but surely eat your surplus.