Whatever happened to the descendants of Julius Caesar and other Roman Emperors/leaders most likely?

Julius Caesars first wife, Sienna, died in child birth. His daughter died in child birth. The guy was surrounded by tragedy. His only son Cesarean was by Cleopatra and as such couldn't inherit anything by Roman Law. Which is why he adopted Octavius. Octavius' father was the husband of Caeser's niece and a friend of Caesar, had been killed in the Battle of Carrhae when Octavius was 10. So it seemed only natural.