A tournament is a short duration player versus player event that players enter with a specific character. They play rapid-fire rounds against each other, with matchmaking occurring within the tournament only. The goal is to accumulate as many wins as possible during the event, so players are encouraged to play aggressive characters that get decisive victories. Based on a player's overall placing in the tournament, he'll win PvP points which allow you to unlock various PvP-specific item rewards throughout a season.
There are different types of tournaments:
Blitz tournaments are a series of duels where players are matched with a new opponent as soon as the last round finishes to get as many victories as possible within the time limit. Tournaments are split between 1v1, premade 3v3, and random 3v3 tournaments.
Free-for-all tournaments take place in the Sarn Arena. They're a massive brawl where players get a point per player kill. Upon death, players are sent to a new arena to continue the massacre.
Capture the Flag Tournaments
There are 3v3 and 6v6 CTF events. These use Swiss matchmaking to control their match structure.
The most competitive of the event types are tournaments with Swiss Matchmaking. These run in a regimented series of matches, where victory is about consistently defeating opponents in best-of-7 play.