LogFAQs > #969912019

series 4 and 5 don't have a starting point like that, you have a chance of unlocking them in any collector's cache or reserve. 2.5% chance for series 4 and 0.25% chance for series 5. I believe series 4 cards have a pity timer where you're guaranteed to get one every X number of caches/reserves but I forget the number, I wanna say it's one series 4 card for every tenth series 3 card you unlock

once you have no more series 3 cards left to earn, that "option" in the prize pool is replaced with 400 collector's tokens. But also after some length of time they will "downgrade" some cards into the next series down