This is a bit unorthodox, but what games feature the Grim Reaper? These are what come to mind:
Castlevania (the only games excluding him are the first two game boy adventures and Haunted Castle)
Shadowgate (It's a sad thing that your adventures have ended here!!)
Kid Icarus (you face him too soon, IMO. If you can get past him in the first stage, it's clear sailing from there on.)
Maximo (I'd like to play Army of Zin to see how he controls in this game)
Monster Party (Welcome! Entrance to Hell!)
Gauntlet (to quote Abe Simpson, AHH! DEATH!)
Any others? I'm sure this isn't all there is. That skeleton guy is everywhere, even... RIGHT BEHIND YOU!!! Yes, that was a cheap attempt for scaring you, and I'm sure it failed. :P