In the new trailer we see the name of the new clan and the name of the city the clan come from.
The name of the city is purgatory.
Purgatory is belived to be the state your soul goes to after your body dies. In purgatory your soul can go to the heaven.
To get to heaven, you will need to walk through the burning fire. If you walk through the fire without burning you can go to heaven.
If you begin to burn, you can't go to heaven with means your stuk in purgatory forever.
Only those soul who are free from greed and other sins can go to heaven.
I think those ghost cowboys, are souls who couldn't walk through the blue fire because of their greed for gold, and there for are stuck in purgatory.
What do you guys think.