Julian Day, primarily known as Calendar Man, is a supervillain obsessed with committing crimes on holidays and specific dates, but he just can't remember his own son's birthday. However, despite this, he’s getting there because he remembers that it’s June-ish.
He was an inmate at Arkham Asylum with Harley Quinn and Poison Ivy before Ivy staged an escape. While incarcerated alongside them, he kept track of how many days Harley had been there which became a point of contention as he was visited by his wife and son and she became annoyed that he would remember that while forgetting his own son's birthday. During Poison Ivy's staged break out months later, he again reminds them of the exact time she has been there.
- ❝ You're giving my explosives to freaking Calendar Man?! What's he gonna blow up, Valentines Day?! ❞
- — Bane[src]
He was shopping at "More-4-Lex Wholesale" where he was behind Bane in line at the counter when his card was declined. The cashier then took back the all the explosives Bane was attempting to buy, giving them to Calendar Man.
He later attended the 83rd Annual Villy Awards where he was seen ordering a drink at the bar and speaking to the bartender. He is later seen sharing a table with Livewire and Catwoman and applauds when Catwoman is announced as the winner of the "Joe Chill Honorary Award".
- Calendar and Date-related Knowledge
- "All the Best Inmates Have Daddy Issues" (flashback; cameo)
Harley Quinn: Black + White + Red
- His head marked with calendar months are similar to the Batman: Arkham Asylum game series.
- This version of Calendar Man seems to combine the gimmicky costume version and the more serious serial killer version.