Cosmas Maximoff (born 29 July 1940) was a male house-elf who faithfully served the New Alexandria School of Enlightenment for thirty-five years before bonding to the Maximoff family. Cosmas was born to parents who had themselves served New Alexandria for decades, and whom continue to serve in the kitchens. Cosmas was a particular favourite of Headmaster Spiros and planned to bond him to his family, though abruptly passed away before that could happen. Cosmas officially began to work for New Alexandria in 1960 as Professor Shapiro personal house-elf, but after the latter took a job at the European Magical University, Cosmas began being paired with dorms.
In 1988, Cosmas was paired with his fourth dorm, that of Pietro Maximoff, Clemente Alborosie, Rawya Zaghloul and Maria Roxha. During their years at the school, Cosmas fostered a close friendship with the four, with the elf being invited to stay in their dorm full-time.