Pokémon Emerald walkthrough/Rustboro Gym

Suggested prerequisites

 * 1) Train all your Pokémon around level 15. The highest level Pokémon in the Gym is level 15, so you need to be around that level or above it to comfortably finish this gym off. Especially if you started with Torchic, it is a good idea to evolve it into Combusken. However, that doesn't mean neglecting your other Pokémon.
 * 2) Have 2 or 3 different Pokémon in your party. A Shroomish or Marill functions well in this gym, so consider catching one of them before you set off.
 * 3) Stock up on Super Potions. You need to have a means of healing your Pokémon to gain an edge in battle. Be aware, though, Roxanne herself has two Potions she might use.
 * 4) Save before and after entering the gym. The first, so that yu can reset if you lose; the second, so that you don't have to fight her again if the power suddenly goes off.

Gym Battle 1: Stone Badge
You can avoid the Trainers if you wish, but they're easy to defeat if you trained enough, and a few extra Exp. Points never hurt anyone. There teams mostly consist of Geodude.

Head over to the Gym Leader: Roxanne!

After you win, you will be awarded the Stone Badge which will help promote growth in the Attack stat of your Pokémon and also allow you to use the Cut outside of battle. She will also give you TM39 (Rock Tomb), the annoying move her Pokémon kept using.

After receiving your Stone Badge and walking out of the Gym, you will see another Aqua Grunt, this time coming out of the Devon Corporation building. He will run off to Route 116, so use the nearby east exit to head there. The north exit leads to Route 115, but there is no use going there right now.