Superman has killed in the comics, showing that even heroes can fall when faced with tough decisions. Various DC characters have met their end at Superman's hands, including Doctor Light and Darkseid.

Secret Six is available for pre-order now, and debuts on March 5 in comic book stores and online. Fans can catch up with all the relevant characters now in the DC Universe Infinite app.

Three years later, Akinnuoye-Agbaje landed a role as DC comics character Killer Croc in "Suicide Squad." His full-body makeover, which involved prosthetics and paint, took over five hours.