How to get the fire ring in diablo 3 prison?

1. Go to the secret camp in Act II and find the businessman in the center of the camp.

2. Click on the merchant interface on the third page of the store, find the atlas of Hellfire Ring and Hellfire Necklace, and purchase the atlas.

3. Kill the key holder in each map to get the legendary portal device.

4. Use the conveyor belt in the first cabin.

5. Get relevant information after killing the boss.

6. Create it using an atlas near the jeweler.