In the summer of 1945, Eric Grate was commissioned by director Alf Sjöberg to create the set designs and costumes for the Swedish Royal Dramatic Theatre's production of Jean-Paul Sartre's "The Flies." The play is a modern, existentialist interpretation of the Greek myth of Orestes, who returns to his hometown of Argos to avenge the murder of his father, Agamemnon.

The assignment suited Grate particularly well given his familiarity with ancient Greek art and, after a long stay in France, with French culture. He was able to draw on these experiences when creating the play's universe through set design and costume.

The idea of the transformative form between humans and the insect-like flies and creatures became significant for Grate's imagination after 1945. Following the costume sketches for "The Flies," Grate developed sculptures in bronze, including "Flugornas försångare" (The Precursor of the Flies) (1945) and the sculpture presented in this auction, "Fågeldemonen" (The Bird Demon) (1946).