Task: Question Generation
Input (English): Apollo and his sister Artemis can bring death with their arrows. The conception that diseases and death come from invisible shots sent by supernatural beings, or magicians is common in Germanic and Norse mythology. In Greek mythology Artemis was the leader (ἡγεμών, "hegemon") of the nymphs, who had similar functions with the Nordic Elves. The "elf-shot" originally indicated disease or death attributed to the elves, but it was later attested denoting stone arrow-heads which were used by witches to harm people, and also for healing rituals.
Output (English): In Greek mythology, who was the leader of the nymphs?