Random Arenas (RA) is an area in the Guild Wars game that allows players to do as much or as little PvP as they wish. Each RA battle consists of two separate teams that are chosen at random and consist of 4 players each. There are a total of thirteen different maps that are also chosen at random.

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Team Arenas (TA) is an organized form of RA. There are still two separate teams with 4 players on each side. Teams from guilds and alliances usually get together for TA battles. Having an organized team is going to benefit the outcome of a TA match. Groups from RA that have won 10 matches in a row are automatically transferred to a TA match.
Either of these two battles is going to work for the Gladiator title track. Make sure that the wins are consecutive to gain points.