That comes from participating in a certain number of events. Eventually I planned to have a choose a title area and it would show all of the titles you've unlocked. You earn them by doing all kinds of things. I can tie them to any metric. Most of them are tied to completing objectives. All of them are based on [Rank][Objective Title] so as your [Rank] in taking on a certain objective changes you'll see things like Skilled, Master, Legendary Grandmaster etc. We all want that Legendary Grandmaster Party Animal title ;)