I just asking here:
I'm not near beating the EX for now. So, what if I beat all of them? Can I only choose one weap for forever? (cuz there isn't a specific weap quest like the relics one).

I have Zenith weap with MNK, but I also sub BRD, which only have the normal relic. I like to have Hellish Claws, but I don't plan to upgrade the BRD weap any time soon, so I might go with the EX Bow then as well. :/