This story seems like a version of the Brothers Grimm. It tells the story of a poor couple who chose the angel of death to be the godfather of their newborn child. That child grew up to become a physician. This physician was allowed by the angel of death to hold a leaf, which if placed upside down means the patient lives and upside down means the patient dies.

Because the physician disobeyed his godfather's orders to save the king (or princess, depending on the versions), the angel of death led him to hell, where the lamps were. According to the Saigonese play, the angel of death held the lamps of the physician and the princess together so that they could live longer. However, in the Grimm story, the angel of death deceived the physician, causing the lamp to fall and the physician to die. Anyway, I myself still love the message of the play better : Today is the happiest day of my life, even though I am the angel of death, I have saved a person's life.

In my understanding, the lamp or the angel of death are both manifestations of the Zoroastrian culture that remained in the Caucasus during the period of Christianization. Zoroastrians tried to preserve their beliefs in remote and hidden places, such as caves. It seems like Peer Gynt : The Gnomes and the Mountain King (Гномы и Горный Король).