Tried the S rank Gach on Hk today. 3 coins a pop. Kinda expensive, right?
In 30 rolls, I got: God, Neue Ziel, Justice and Master. [C2, at Skill 1]
The chance is freaking higher than getting a B rank.
You can roll absolutely ANY S rank released to date. Some guy was lucky and rolled a Nataku EW and a Sandrock EW. Meh.