John Ashley, a veteran of AIP beach movies and Romero's frequent star, plays Joseph Langdon, an American deserter from World War II who leads a criminal existence in the mountains. The Philippine military has finally cornered him after a particularly heinous crime, and things look bad for Langdon, who'll do anything to survive. He gets an offer from Vic Diaz, another Filipino genre stalwart, who plays a Satan gone native. Langdon readily sells his soul and sets about the Devil's business.
The boss sends Langdon forward in time to possess the body of businessman Phillip Rogers, mangled and presumed dead in a severe accident. Rogers's wealth and power should give Langdon ample opportunities to fulfill his mandate of corrupting people and spreading evil. He does his bit by sacking his entire board of directors, but balks at doing evil to Rogers's wife, who throws herself at her restored-yet somehow altered husband with naked abandon for some R rated loving to the romantic music of Nestor Robles.
Overall, His Satanic Majesty is dissatisfied with Langdon/Rogers's performance. He gives him fresh incentive to do evil by inflicting on him what looks like a severe abdominal cramp. Our poor antihero goes into a sort of toxic shock, emerging as -- I guess -- a beast of the yellow night. Fright-wigged, face blackened and gnarled, his dyspepsia turns murderous as he takes his pain out on random victims, slashing throats, lopping off limbs, ripping out hearts in one bestial stroke, until the agony goes away.
Soon the police have a murder spree to investigate, and the lead inspector sees in Phillip Rogers the face of Joseph Langdon, the man he'd hunted down years before. Rogers draws suspicion upon himself by staggering home in the mornings after his rampages wearing a bloodstained shirt. During one such overnight, the BYN finds unlikely shelter in a warehouse where an old blind man hangs out, a former bandit himself and hence someone who can empathize with Langdon. He has a strange calming effect on the beast, whose problems only grow when he returns to normal and faces growing suspicions from the authorities. Concerned citizens draw their own conclusions as mobs threaten Rogers. One indignant individual gets through a police cordon and stabs Rogers. Inspector Santos is troubled to learn that Rogers is unhurt.
Langdon still has a measure of free will, which his master tries to constrain with fits of pain and murder. Later, to prove a point about Langdon's own irredeemable evil, Satan tells him that future transformations will be self-generated. The blind man encourages him to save himself, and as Rogers, Langdon works up the will to renounce his wife. But her insistence on loving her husband puts her in mortal peril as lust and guilty conscience suffice to awaken the beast....
Beast of the Yellow Night is ripe exploitation with a fair amount of horror y sexo to keep us interested, but the movie has some spiritual concerns as well. It has an unusual ending. Langdon and the blind man have fled into the countryside and are pinned down by flamethrowers in some kind of field. The old man is shot and captured while Langdon transforms once more into the BYN. As the attempted assassination earlier demonstrated, the beast is invulnerable. Bullets can't stop it. But he's drawn to the dying old man, who implores the monster to pray for him. Strangely, it seems to do so, though I'm not 100% certain of this. It is certain that the beast undergoes an important change. because after this touching moment, the army guys are able to blow him away.
Unlike the Retromedia edition advertised in the picture above, the Mill Creek Entertainment DVD of Beast (part of the Nightmare Worlds box set) is fullscreen, but this is one of those instances in which the limitations of the truncated image strongly suggest that the movie actually made good use of the widescreen frame. While the Beast makeup is pretty unimpressive, the movie looks respectably budgeted overall, and Robles's music is pleasant enough. Some of the Beast's fight scenes are nicely energetic, and Diaz is entertaining as a mildly campy devil, but as a whole Beast of the Yellow Night is more interesting than good.