As mentioned before, Calendar Man was a serial killer. He chose his victims based on the date.
Generally speaking, he preferred killing on Fridays, because the next day was Saturday. People did not have to work and could rest at home, meaning the largest number of people would see the news about his murders.
Of course, sometimes his plans did not go smoothly, or he felt he was not getting enough attention. Then he would choose to kill a few more people on Saturday, adding a little fuel to the fire.
His signature method was to draw circles on the calendar in a victim's home. If the victim did not have a calendar, he would draw one on the victim's body, then circle dates on it.
His motives, when it came down to it, were very simple—just the sort of thing old Gotham natives loved. His random killings were merely to play games with Batwoman. He did not rob for money or sex. He just played.
As a frequent visitor to Arkham, he might have been one of its rare successful treatment cases. After getting out for the last time, he really did stop killing. He retired and went to work for Channel 52, and could now be considered a neutral figure.
He did a good job. Whenever there was news of a murder scene, he could offer highly professional opinions from the perspective of a killer. He had also taught himself psychology and forensic science, and ran his own popular Facebook account.
As one of the United States' most notorious serial killers, having murdered over a thousand people in Gotham over several decades, he had an extremely devoted group of female fans. Those women loved serial killers, which made his signed calendars very valuable.
There were plenty of serial