In Divinity: Original Sin 2, how to get the championship chest in Divinity: Original Sin 2 Driftwood Arena can be found as follows:
1. First, players must defeat the people in the Driftwood Town Arena and get the treasure chest key as a championship reward.
2. The treasure chest corresponding to the key is in the basement. You can choose to enter it by teleportation or phoenix dive.
3. There are many nozzles in the basement that will emit petrifying mist. There is a valve in the room between the first petrifying door and the second. If you turn it off, there will be no petrifying steam, and then you can get the treasure chest.
