Trophies are the basis upon which status is earned. Trophies can be gained or lost when attacking or being raided.
Trophies are used to calculate the game ranks where Leagues and matchmaking are based on.
Every time you play a multiplayer battle you will either win or lose trophies. This is also applied to multiplayer defenses.
If you win an attack or defense, you win Trophies. If you lose an attack or defense, you lose trophies.
As you climb up your trophy count you will find stronger players, but will get better League Bonus and Village Guard times.
The number of Trophies available to steal is based on the Trophy difference between the attacker and defender.
If you attack someone from a lower league, you will have only a few Trophies to steal and a lot to lose.
If you attack someone with more Trophies than you, you will have many cups to steal. On this case, you will have only a few cups to lose.
If the attacker and defender have the same Trophy count, the attacker will get 30 cups in case of victory and the defender will get 20 if successfully defends.
The minimum trophy offer on attacks is currently 6 Trophies.
Once you reach 5.000 Trophies you join the Legend League that features a completely different trophy calculation.
Matchmaking is based on Trophies and Town Hall level, except in Champion League and above, where only the Trophy count matters.
Above 5.000 Trophies you will join the Legend League that features a completely new matchmaking system.
Since each player can intentionally gain or lose Trophies as they desire, you essentially have control over how hard you want your opponents to be. This means that a level 11 Town Hall can come and ruin your day if he wants, just because he ditched Trophies and ended up with the same Trophy count as you.
However, the game wants you to play against player with the same Town Hall level, this is why there is a loot penalty for attacking lower Town Hall levels. You can find more information about this on the Loot Calculation page.