How do you unlock the 8th gym in Pokemon emrild?

Answer 1

To unlock the gym at Sootapolis, you must first complete the Aqua/Magma stage of the game. If you have not done so already, you must find Team Aqua's Underwater Hideout. This is a cavern beneath the water and can be reached using the HM Dive.

Once you reach the hideout, you must make your way through it, and once you defeat the leader, it will start to rain. When it does, fly back to Sootapolis, where you will need to talk to Steven. He will show you to a cave in the city, which you must enter to find Wallace. He will ask you where Rayquaza is; tell him the Sky Pillar, which is located in Pacifilodge. He will then leave.

Now you must go to Pacifilodge. There is a narrow breakaway from the rocks. Go through it, follow the short path, and you will see a big tower. Go inside and through it. When you do so, Wallace will talk to you, tell you to find Rayquaza, and leave. There will be an even bigger tower, inside of which is Rayquaza. Find him, then return to Sootapolis. There will be a short cutscene, and when it ends, the gym will be unlocked.