what are the drop rate ??

farming for a week.and really its so strange the drop is nothing. even the chaos rifts . same .
so we cant buy then and we cant get with a good amount in farming. what we should do . and we need them for many things . at least sell them so we can buy them in the game shop

You can always get Chaos Core on Loot Chest, if you have 200 Chaos core save at least 100 chaos Core for later use and Hoard more Loot Chests, You must be one of those who never save up some materials because you're in a Hurry to get higher CP. I started with atleast 50 Chaos Core and I never complain with anything... You want Chaos Core? Farm More, Hoard More Mats and be Patient You'll get what you want in the end.