Ben Tennyson is the titular protagonist of the Ben 10 franchise. He is a 10-year-old boy who found the Omnitrix, a powerful alien device that allows him to transform into various alien heroes. In the original series, Ben is shown to be immature, cocky, and selfish, often making jokes even in serious situations. However, he is also heroic, caring, and good-natured, always willing to save others. Despite his immaturity, he is good-hearted, noble, and loyal, always willing to save others.