Just make up lore out of thin air. Duh, how do you think it got there in the first place. U do realize your playing a video game right. It would make sense to add more classes, else you will get very bored with this game in a few years. I think with destiny 2 they should add new supers pertaining to the subclasses that already exist. Meaning a new Super for solar, ark, and void. With the same characters we have now