[1] The character was inspired by science-fiction writer Harlan Ellison suggesting to O'Neill that he writes a story about Nazi war criminals.
[2] Created by writer Mike W. Barr, and designed by artist Alan Davis, the Judson Caspian version of the Reaper first appeared in Detective Comics #575 (June 1987), the first part of the four-part Batman: Year Two storyline.
[3] In Tony S. Daniel's "Batman: Life After Death" story arc, Hugo Strange resurrects Gruener and manipulates him into becoming a mass murderer.
[9] As the Reaper, Caspian wears a large hooded black cloak with armored red leather or cuir bouilli, which prevents bullets and punches from affecting him.
The knees and elbows of the red leather armor are tipped with spikes that add more power to blows Caspian inflicts.
Caspian also wears a skull-shaped mask with hooks on the mouth to cover up the lower part of the face and red glowing eyes.