On your way 2 Sunnyshore city, you'll encounter 1 of the elite 4. after u beat him/her they will be on their way 2 the Battle Frontier
yes
elite 4
No, but the Frontier Brain of Sinoh is there as an Elite Four member.
Beat Elite Four.
you will go to Battle Frontier
you half to beat the elite four and go in the ferrie in lilycove and click on battle frontier
Beat the Elite four and the Champion.
battle frontier, take the boat that is in snowpiont
You can get to the battle frontier after you beat the Elite Four
By dying
when you beat elite 4, steven will call you after that, go to lilycove city go in a place there will be ship talk to a lady you will go in the ship to get of the he will say go to room 2 sleep in the bed then you go to the battle frontier