Free Thundergun

This side quest has players complete all challenges from each of the five challenge totems to obtain a crate key from the Hermit which you can use to unlock the crate in the Lighthouse Level 4 to obtain the Thundergun.

Each totem has three challenges, meaning you'll need to complete a total of 15 challenges to obtain the crate key.

Challenge Totem Locations

Once all 15 challenges have been completed, you can claim your crate key from the Hermit and unlock the Thundergun Crate.