by using ur powerful weapon
Do A 100-Battle Streak.(or finish 100 battles in a row.
emerald:Beat Battle frontier/tower or Catch Regis
You don't have to do anything, but you can do battle sims, battle bingo, or you can go back to the city and finish what you went there to do.
Go to the ferry in snowpoint city and play in the battle tower or get all the legends your choice
you get BP(battle points) by battling at the battle tower in the battle zone(lolz) after you defeat the elite four and the and finish your pokedex. then you can trade your battle points for stuff liker are candies or TM's
There is none, but after you finish team battle EX-6 you can find it in any tower level.
you cannot ever beat the battle tower. but if you have completed the sinnoh pokedex then the battle tower will help you complete it. you can battle at the battle tower as long as you want.
Mo battle tower
after you get contunious battle wins at the battle tower
you cant beat the battle tower
after you battle 7 trainers in the battle tower you will get 3bp
The Battle Tower is in the Battle Frontier, which is north of Route 40.