The Mask of Bara played a critical role in the history of the Polvora Empire. Since I am unable to continue the RP (it turned out to be much longer than I anticipated), the new plan is to put it into lore directly and speculate on what would happen.
The Outcomes
These were the end scenarios I initially had planned. Of course, we can change these as we see fit.
UPDATE: 2b seems to be the most favorable option.
Scenario 1
When the party arrives at the volcano, they discover Polvoran soldiers stationed there. They agree to get the mask, but they later get taken into custody and delivered straight to Castle Bastillo to ensure the mask is transported safely. The player who touched the mask gets executed while the others are let go and rewarded. Prince Barago gets his mask and begins his experiments.
Scenario 2
The party decides to steal the mask for themselves as Anton suggested. They track down the four stone giants and slay them all, unleashing Bara herself. However, it turns out Bara wants nothing more than to be left alone. Anton wants Bara dead, but Prince Barago wants her captured.
Scenario 2a
Either Anton or Barago get what they want, getting the players on the bad side of one faction. Most likely, they ally themselves with the opposite faction.
Scenario 2b
The players let Bara go and get on the bad side of both factions. The players become refugees.