The artwork and character sprites for Twenty Three Seven looked interesting so I went ahead and tried out the Closed Beta. I actually thought it was going to be a full-blown RPG, but as it turns it out, it was mostly a casual auto-play RPG. The gameplay is fairly simple, you swipe left to speed up your characters turns, swipe down to charge up your fever mode, and swipe right to block attacks which consumes your shield. You can also summon random units or helpers during battle. I didn't really like the game so I ended up abandoning it, even after rolling three SSR characters!
Game Site: http://23-7.jp/