Ben Tennyson is a fictional character and the main protagonist of the animated series Ben 10. He is a 10-year-old boy who discovers a mysterious device called the Omnitrix, which allows him to transform into various alien species, each with unique abilities. Throughout the series, Ben uses his powers to fight villains and protect the Earth. He is known for his bravery, quick thinking, and strong sense of justice. As he grows older, Ben continues to face new challenges and adventures, often alongside his cousin Gwen and grandfather Max.