A key issue noted for First appearance of Little Boy and First appearance of Jonny Billy. Batman #621 was published by DC Comics on January 1, 2004, as part of a series that began in 1940. Brian Azzarello writes, and art comes from Dave Johnson, Eduardo Risso and Heroic Age. This 52-page issue features Batman, Killer Croc, Batman Who Laughs, Crispus Allen and Agent Graves, among 7 characters cataloged on VerseDB.