Shinigami no Ballad.

In the darkness stands a girl draped in pure white. Don't let her innocent appearance fool you; her hands grip a glistening scythe. Momo is the dark messenger of death who, along with her wisecracking cat named Daniel, is tasked with releasing humans from their mortal bonds and delivering their souls to the great beyond. First encounters with Momo always end in farewells.
(Source: Seven Seas Entertainment)