Usr signature cards rank first in rarity and legend. A box of 20 packs, 10 pack can be filled with star cards, so there is basically no card slot, and it is basically disassembled every time.
Now after the revision of the legendary version, I feel that in order to open usr signature cards, there are 2 cards in a box and 18 cards in one game. Collecting all these means you have to open at least nine boxes, and you have to be very European to avoid repeating one.