From publisher blurb:
All living things must die. The multiverse is a fantastical place filled with wonder and mystery, but that one fact is true across all the planes. Not that heroes or adventurers are concerned, since surviving party members can just track down a cleric who will resurrect them for a generous donation to the temple. But such actions have consequences, even upsetting the delicate cosmic structure of reality.
And when that happens, a reaper arrives to balance the scales.
Reapers don't care if a hero is good or evil. They aren't moved by pleading, bargaining, or curses. It's not even clear if they can be killed, since the few who claim to have survive a reaper tend to die a few short years later. All that matters to them is restoring the cosmic order of life and death.
You can hide behind protective spells. Move from one safe house to another. Perhaps even challenge them to personal combat (which they'll gleefully accept). But one way or another, the reaper earns its due. It's just a question of when.