Trophies are earned in battles.
Winning a battle awards trophies to the player and removes trophies from the opponent.
Losing a battle removes trophies from the player and awards trophies to the opponent.
Drawing a battle does not affect trophies from the player or the opponent.
Earning certain amounts of trophies allows a player to progress to different Arenas while losing trophies can force the player to return to a previous Arena.
Friendly Battles do not affect trophies.