early on you can p2w and get end game cards, as soon as you clear the first campaign, elaria. then the chance pack or box that is currently on is available to buy with shards.
You don't have to pay to play, but if you pay real money you get a definite boost, and if you pay enough money you can have a hugeboost compared to other players who have spent the same amount of time playing, but haven't spent irl money. this game is definetly P2W, but I haven't payed ay money on it.