Real Name: Doctor Gruener
Occupation: Criminal
Marital Status: Single
Base of Operations: Gotham
Height: N/A
Weight: N/A
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Hair: N/A
First Appearance: Batman #237 (December 1971)
Created By: Denny O'Neil

Doctor Gruener was a German Jew who had been the inmate of a concentration camp run by Nazi Colonel Kurt Schloss, the murderer of Gruener's parents and sister. After the War, Gruener settled in the United States. As an old man, he took on the masked identity of the Reaper (not to be confused with the Reaper identity taken on by Judson and Rachel Caspian), and killed Schloss during the Halloween parade of Rutland, Vermont. When Batman interfered, the Doctor regretted that he had become a cold-blooded killer himself. Shortly afterwards, the Reaper fell off a cliff, the Batman being unable to prevent his death.