No no way what are you thinking faty faty bom bom idiot
They don't get sronger, but your Pokemon will get stronger if you battle them a lot.
Go to the battle tower
There are 69 trainers you can battle in Pokemon Sapphire. This also includes the Gym Leaders and the Elite Four.
in Pokemon emerald simply beat the elite 4 then you will be invited to the battle frontere then find it but it is not in sapphire or ruby sorry bout dat
You can battle your friend at any time you don't have to beat the elite four.
The elite four will open and they will be stronger and you can now trade with ruby, sapphire and emerald.
He is the Elite Four Champion. You battle him in the Elite Four.
You have to beat all gym leaders and the Elite 4 and Champion.
The credits roll and the Elite Four's Pokemon get a slight bit stronger.
In Pokemon Sapphire, Steven is the Champion. If you want to find him, beat the Elite Four. In the next room he'll be waiting ready to battle you.
After defeating the Elite Four once, their Pokemon are much stronger than before, and with new Pokemon. There is no new Elite Four to battle, though.
After you beat the Elite 4 in Pokemon sapphire, latias will be in the wild in random places. I suggest you keep a master ball because latias always runs away in battle when you incounter it.