The Eighth Doctor and Sam visited Entusso and stopped many alien invasions during their visit. After these visits, the people of Entusso saw the Doctor as a hero and treated him as the defender of their world.
Later the Doctor visited Entusso again with his companion Fitz and found that a company called Alien Defence Incorporated (ADI) had used the Doctor's image to gain money for protection from aliens. The Doctor and Fitz put a stop to this and made sure that ADI built their reputation themselves. (AUDIO: Fitz's Story)