A German art curator who spent time teaching Stella nuances and invited her to his art gallery in Shirakawa-gō, Gustav had a brilliant career that lead him to travel the world, curating exhibitions for a multitude of museums and galleries. His extensive knowledge of art, history, and architecture sometimes makes him come across as a smug intellectual. At a relatively young age, Gustav developed multiple sclerosis. His condition physically paralyzed him, but left him with a clear mind.