Yes, he's a fictional character. Burt Lancaster played the part with real gusto, and it was quite an entertaining film.

If you want to see some absolutely chilling examples, Rig, of what extreme anti-religious and proudly atheist fanaticism can do...rent the movie "Seven Years in Tibet", watch it through, and see what the Maoists did in Tibet in the 1950s.

Then watch some documentaries on Pol Pot and the Khymer Rouge who managed to kill about 1/3 of the entire domestic population in their own country in just a few years of organized insanity. They were atheist fanatics too.

Fanaticism can take any conceivable viewpoint and turn it into a murderous obscenity.