Scythe by Neal Shusterman (2016)

In a future where humanity has conquered death, the only people who can end a life are “Scythes” — trained reapers who decide who dies to keep balance. Two teens become apprentices and quickly discover the system meant to preserve life might be more corrupt than death itself.
Shusterman’s writing is sharp, his moral questions razor-edged, and the suspense relentless.

Rating: ⭐⭐⭐⭐⭐