An evil spirit, raised from earliest stages in the wake of being summoned by and safeguarded from the Nazis, grows up to end up a shield against the strengths of haziness.
In the final days of World War II, the Nazis attempt to use black magic to aid their dying cause. The Allies raid the camp where the ceremony is taking place, but not before a demon - Hellboy - has already been conjured. Joining the Allied forces, Hellboy eventually grows to adulthood, serving the cause of good rather than evil.