The first campsite guest you get in New Horizons will always have a smug personality, so there is a chance it might be Marshal. It’s essential to keep in mind there are thirty-six additional smug villagers it could be. So there's a one in thirty-six chance Marshal will be your first campsite guest. My first campsite guest was Axel, and my second was Pietro. I’m not lucky enough to have found Marshal that way - but he lives on my island after inviting him with an amiibo card.