The battle area is set in what appears to be the inside of a volcano, the battle platform surrounded by magma.
Battles here are carried out in a round-robin tournament style, and is the only Colosseum you can risk losing a battle in, all that matters is having the most points overall. For each victory, you gets points for how many Pokémon you have remaining on your team. If you have the highest score at the end of the round-robin (5 matches), you will get to face Terrell.
The League Chart. Shown here, the player has a perfect score.
Battle Name: League Battle
Availability: Open after beating Sunny Park Colosseum