Hello all, I've just recently started battling a bit, and I've come across all those cool cash shop challengers, but most of the summoning items are retired. Since I don't want to spend millions of sp on them, is there any kind of rotation or special sale time when they are available again? Thanks!

For the past two years all retired CS challengers have made a comeback during Black Friday sale in the Cash Shop. The only exception is the challengers from the current year because the series haven't completed yet. So for example if you miss a challenger in Feb this year you'll need to wait until Black Friday sale 2018 to buy the unlocking item. Other than that, I'd recommend keeping an eye out on the BF sale this year.

Keep in mind also that the challenger items have been brought back, however they're some of the few items that actually don't get put on a sale price. So if they do come back again, you should expect to pay full CSC price for them and not like half off or anything.

Great, I was hoping for something like this! I'll keep an eye out for sales then :-D Thanks a lot for your answers!