Tickets are needed to enter the arena. The higher the arena the higher the difficulty but the better the rewards you get, including trophies and arena chests. Please note that you don't automatically get an arena chest by winning. Every arena has its own chances to drop an arena chest. The higher the arena the higher the chances to get a chest from every victory.

Once an hour you can get free tickets from your wise mentor, but you can also purchase them for gems or get them for watching ads.