A death mask can be crafted if one obtains a rare clay that is very rarely rewarded when pouring Wine of the Dead over living resources to deplete and remove them.
Once crafted, the death mask can be displayed on a table in your home, or put on the wall.
Much like an icon, death masks periodically bestow gifts to their owners, specifically time increments that can accrue and are used at the next trip to the ancestral lands.
ETA: I forgot to mention, that you have to craft your death mask by taking your clay down to Hell to a hellish kiln. Yes, a hellish kiln...which is also a good name for a band.