Why Death Masks?

[WereElephant]

This could easily be my general density speaking, but I don't understand the reasoning behind that choice of name for book 5. There were no masks in play in the book. There was death, sure, but that's hardly a distinguishing feature in this series. Quintus Cassius had a "mask" in the sense of being disguised, but that's only one mask, not multiple.

The closest thing I can come up with is that the Denarians themselves are metaphorical death masks for the people they used to be. It still feels wrong, though. What am I missing? Is there a blatantly obvious pun or connection here I'm just not getting?

[Mr. Death]

A death mask, traditionally, is a depiction of the deceased's face that's often made from a cast of the corpse itself.

The Shroud of Turin is traditionally believed to have a depiction of Christ's face on it, and is believed to have been "imprinted" with his face as he wore it in the tomb.

So in a way, the Shroud itself is Christ's "death mask."

[WereElephant]

A death mask, traditionally, is a depiction of the deceased's face that's often made from a cast of the corpse itself.

The Shroud of Turin is traditionally believed to have a depiction of Christ's face on it, and is believed to have been "imprinted" with his face as he wore it in the tomb.

So in a way, the Shroud itself is Christ's "death mask."

I did not know about the face imprint on the Shroud. That makes more sense. Thanks!