In the Arenas of Oz you can choose a hero and companions to battle in real-time PVP. Whenever you defeat an opponent in the Arena you will be awarded a star, defeating a leader will earn you 3 stars. The stars you are awarded go towards a Star Chest which is unlocked when you have 15 stars. You will also earn and lose trophies depending on how you perform in the Arena, and get ranked against other players globally. As you earn trophies you will be promoted into new leagues where the rewards get better and new companions become available. Note: You can only claim 1 Star Chest every 8 hours.