Is it worth to max all of hans skill to lvl 10 using Crystallized Lore ? I use him a lot cause i dont have any other crit supp, but i expecting to get a better supp like weaver in the future.
Because Crystallized Lore is a rare item, should i save it or just use it on him ?
It isn't that rare tbh
You can get 1 or sometimes more lore per event and probably still won't spend it all because it's harder to get all materials and QP for levels 1-9 than get one lore
I, for example, have 17 pieces of it and don't have much to do with them
As Ritsuka said, it's not that rare and you'll be swimming in them the more you play and participate in events. Hans is a great support servant and maxing his skills to 10 will help you immensely in any sort of battle.
Even if you get Waver, they can still go hand in hand and support your main DPS servant.
