don't exactly know what that is cause I haven't actually fully beaten a pokemon game yet :|
I know I probably shouldn't be the one doing this but eh
anyways if you could tell me what it is exactly that would be nice.
In Emerald (the one with the not-stuff frontier) the Battle Frontier was a location that you can go to once you beat the champion thats got a bunch of fancy gimmicky arena thingies.
There's the Battle Tower, the same as its always been in every other game, just fight dudes on every floor til you reach the top and fight a boss
The Battle Pyramid, where you're forced to stumble around a dark maze trying to find your way to the next floor, all the while being attacked by wild pokemon and the only way to increase your vision is to fight trainers
The Battle Palace, where you don't get to directly control your pokemon, instead they fight based on their nature (total luck but fun to watch)
The Battle Factory, where you choose some rented pokemon, and can trade them for those of the trainer you just defeated after you beat them
The Battle Dome, which is a 16-trainer tournament
The Battle Arena, which i forget exactly but its some karate-ass stuff
and the Battle Pike, which takes place inside a giant seviper building full of random events.
beat the battle buildings, get battle points, buy special items with them