So I just noticed I have over 500 Rainbow Medals. I'm not sure how, but I do.

How often are new characters added to the exchange, and do the characters/medals ever expire? I really...really want this girl, who should hopefully be released soon via the gacha. I'm willing to wait to exchange for her, assuming I can keep my medals around until then.

https://xn--eckq7fg8cygsa1a1je.xn--w...83%AA%E3%82%A2