Hellboy is a fictional character created by writer-artist Mike Mignola. The character first appeared in San Diego Comic-Con Comics #2 (August 1993), and has since appeared in various eponymous miniseries, one-shots and intercompany crossovers. The character has been adapted into three live-action feature films. Two starring Ron Perlman in 2004 and 2008 in the title role, and one in 2019 which starred David Harbour, as well as two straight-to-DVD animated films, and three video games – Asylum Seeker, The Science of Evil, and as a playable character in Injustice 2.

A well-meaning half-Demon (or Cambion) whose true name is Anung Un Rama (and upon his brow is set a crown of flame), Hellboy was summoned from Hell to Earth as a baby by Nazi occultists (spawning his hatred for the Third Reich). He was discovered on a fictional Outer Hebrides Island by the Allied Forces; amongst them, Professor Trevor Bruttenholm, who formed the United States Bureau for Paranormal Research and Defense (B.P.R.D.). In time, Hellboy grew to be a large, red-skinned adult with a tail, horns (which he files off, leaving behind circular stumps on his forehead), cloven hooves for feet, and an oversized right hand made of stone (the Right Hand of Doom). He has been described as smelling of dry-roasted peanuts. Although a bit gruff, he shows none of the malevolence thought to be intrinsic to classical demons and has an ironic sense of humor. This is said to be because of his upbringing under Professor Bruttenholm, who raised him as a normal boy.

Hellboy works for the B.P.R.D., an international non-governmental agency, and for himself against dark forces including Nazis and witches, in a series of tales that have their roots in folklore, pulp magazines, vintage adventure, Lovecraftian horror and horror fiction. In earlier stories, he is identified as the "World's Greatest Paranormal Investigator