The Hellboy Universe is the fictional universe of the Hellboy comic and its various spin-offs, created by Mike Mignola. Its first appearance was in a black-and-white, four-page promotional comic by Mike Mignola with a script by John Byrne published by Dark Horse Comics in San Diego Comic-Con Comics #2 (19 August 1993), distributed at the San Diego Comic-Con. There are currently 52 trades and 2 OGNs in the series.