I’ve been having a difficult time getting Drake Rider from the newest kingdom. After getting well over 50 ultras from cards, I decided to buy him in arena. It cost 75 Gems to get the Drake Rider and level 10.
Of course, the first key awarded from the same arena dropped Drake Rider right in the center. I paid 75 gems to get the card 20 seconds earlier than I would have with keys. Oh well, at least I have him level 10 already, which is nice.