FRYEAN MYTHOS: *adventure*
CAMPBELLIAN FUNCTION: *sociological*
This is the only solo Blue Demon film I've seen translated into English, and there's not that much to say about it.
The opening scenes are moderately bracing, as a thief dressed like the superhero-wrestler Blue Demon kills a diamond courier and beats down a hotel bellboy. The script calls a little attention to the fact that the thief could have killed both victims but didn't-- but it seems like the writer just forgot this point and went on to other things.
The cops don't entirely disbelieve the possibility that the real Blue Demon might have gone crooked, but they allow him to continue his own investigations. Whereas the prototypical Santo mostly played a lone hand, Blue Demon in this entry has one male and one female assistant, which may or may not have been a regular thing in his solo movie series.
There are actually two villains behind the imposture, whom the wrestler-hero sent to jail years ago (though, again, I've no idea if they actually appeared in an earlier film). The mastermind is named The Count, though he doesn't do much, and the bulky guy who impersonates is an ex-wrestler named The Cossack. Eventually the two Demons square off for the film's best fight, though for some reason the Cossack gets away and shows up in another disguise to attempt conquering his foe in the ring. Not the most sensible plan-- even if he'd killed the Blue Demon, he would've been trying to escape in front of dozens of people.
Both the hero and the villain have a comely blonde helper who does a second or two of fighting, so DEATH NIGHT scores a couple of points in the "girl power" category, not at all that common in a luchador film.