It accommodates a particular sort of fan service, one that lets enthusiasm mutate into participation. It’s goofy nonsense designed around the story-breaking premise that you, the player, need to be included in everything. If that premise sounds like the stuff of fanfiction, it absolutely is. To do this, you create your own original character to fight alongside the heroes from the manga and anime, jumping from critical moment to critical moment: standing on the sidelines at every important battle, delivering the saving blows.
As a 'Time Patroller,' your job is to maintain the Dragon Ball timeline, even as evil trans-dimensional wizards and warriors try to muck it up.