"Seventeen years, and no one can even really give them much of a challenge anymore." Except him. "When I was 14, my Master fought back against them--I think he prevented it from being worse up until then...but he and I were the only ones."

As for why? Oh Trunks could speculate easily enough as he scowls. "They haven't, because they find it all to be a game. As long as they're amused...things stay more peaceful. Those of us left have started learning how to hide, and have small resistance movements. But we're surviving." Don't mind the bitterness and hints of anger; it's well-earned

For Bulma, and for Trunks--mere survival was not enough. They would do their best to make sure the people of Earth thrived again if they could.