Grim is the Reaper
or: Big Bad John
When Big John Buscema drew a bad guy, you knew he was bad. We didn't need back stories of stolen lunch money or sand in the face. His baddies were bad simply for badness sake.
Looking at the Grim Reaper on the cover of Avengers #52 we see John at his malevolent best. This is a guy that kicks puppies, eats babies, puts ketchup on hot dogs!
The Grim Reaper!
Happy Trails
Smitty