Edit. Garbage. The drop rates have been nerfed for non paying players. I used to get s rank every 3 to 5 10-pulls but now it's more like one S for every 100 pulls. Shameful and greedy developers. You pretty much need S teir stuff to continue the campaign. 100% pay to win. How bad this game has gotten is beyond me. I'm now at 120 pulls and no S drop yet. Casual player beware. Unless you want to spend $35 to get one S teir pull. 100% pure greed.