sickeningly beautiful

A tragically beautiful person. Someone who remains beautiful (not necessarily in a skin-deep sense) through treachery and hardship.

For example, it's the end of the world, or in some dystopia after a large battle or some kind of tragedy.

"God, even in the ashes, covered in blood, dirt and other grime, they're sickeningly beautiful"

or

Possibly at a funeral, or maybe in the ER.

"Even after everything that's happened, they remain sickeningly beautiful, even in their grief"