Well, if you think about it, a Reaper is an "Angel of Death."
And angels are typically depicted as guiding lost souls. Really reapers aren't forces of evil as much as they just take people away when it's their time indiscriminately.
After reading emotionless emotional kun, this is truly a manga that restores some faith in humanity. It is pretty much exactly that premise, but fits the title better (despite having another instead), and the mc is not a little piece of shit that makes me angry.