With the recent disclosure of his identity, Ben has become a worldwide celebrity. After Ben's last battle with Vilgax which resulted in the destruction of the Ben 10 Omnitrix, he replaces it with the new Ultimatrix that allows him to evolve his alien forms into their ultimate forms.
Who doesn't want to save the Earth from aliens' invasion? Can I see some hands up in the air? That is right! You won't sit around and do nothing, am I correct? So, what are you waiting for? You must have some skills to fight the extraterrestrial life, I am sure of that so jump in for the ride.