nothing happens. you just beat the battle frontier that's all.
it is have a new island
Arceus is not on battle frontier!
If you speak to Scott (the manager of the Battle Frontier) he will reward you with exclusive Berries.
you have to beat the battle frontier brain
as in battle frontier
There is no battle frontier in fire red
There is no Battle Frontier in Pokemon LeafGreen
talk to Scott and get a prize
The credits happen, and then you are allowed to visit the Kanto region and battle trainers there.
No, Pokemon Sapphire Version does not have a Battle Frontier. However, Pokemon Emerald and Pokemon Platinum do have the Battle Frontier.