Arno is a little wannie from the Island of the Wannies. He lives in the Village of the Wannies with both his parents, and likes to play with his toys there. His mother makes a suposedly delicious firefly tart, which Twinsen can eat, getting a slice of it. When he is told that it is a firefly tart, he faints. Later, he can give the slice of tart to the old man to get the key to the chapel.