In this function, you can spend coupons or gold (1 free chance every day) to get rewards such as partners (purple, orange or red), materials to evolve your characters (Partners, Akatsuki, Eight Gates), skill manuals.
By spending coupons, you will also get 1 point of luck. By spending gold, you will get 10. The more points of luck you have, the better chance you will have to get Pain. However, if you get the 2000 points, you will get Pain at 100%.
Here the link to the discord: https://discord.gg/cZNdapx