You will know immediately what is meant with the title when you see this image with the reward cards from the last completed quest.
It was a struggle. I don't play much and my rank is low. Add to it bad luck with the splinters for the quest. Fire and Death, even Earth are useless with my cards.
Water is a whole another story. With them, I can beat, most of the time, even the classical Life setup. Sea Monster and Ruler of the Seas can do wonders :)
How are you coming along this season? Playing tournaments or chasing quests? Good luck in any case!