Grell is a grim reaper, a divine being sent to collect the souls of the dead. He is part of the grim reaper dispatch division.
Grell has long, dark red hair, shark-like teeth, and red-framed glasses which are accessorized with a neck chain containing skulls. His typical attire consists of a suit, gloves, bow tie, and high-heeled ankle boots. Additionally, he has a red coat, that he has confiscated from one of his victims, which he slings off his shoulders and wears around his elbows. He is described as "covered in red."
Grell also has another form that has long brown hair, usually tied back in a low ponytail. He teeth also resemble a humans and his eyes don't glow. Grell usually uses this form when he has to interact with humans for an extensive period of time.
While he can come off as aloof and even heartless and bloodthirsty, Grell can actually be sweet and caring when the time calls for it. He is obsessed with the color red and all things of beauty in general. As a grim reaper, Grell is very passionate about his work, almost to the point of being over joyed by the prospect of ending a life.
Grell has specially modified his Death Scythe to operate like a chainsaw, because he says the average Death Scythe is old-fashioned. He claims that it is of first-rate quality. His weapon seems to perpetually be in his possession.