When Cam was fourteen, he found out that his adopted family were hunters. He started hunting with them when he was eighteen. A few years ago, he and his brother found a newly turned vampire who claimed she'd never hurt anyone. Cam believed her and wanted to help her, but his brother killed her without hesitation. It led to a crisis of conscience for Cam, since he began seeing the supernaturals they hunted as human rather than monsters. A few months later, he packed up his things and walked away without a word. His family likely thinks he was killed on a hunt.
In the app, I called the brother Marcus, but that can be changed. He's at least six years older than Cam, and while they were growing up, Cam always looked up to him. Even though Marcus enjoyed hunting, and never saw supernaturals as human beings, he wasn't some kind of bloodthirsty psychopath. When hunting, he was merciless and aggressive, but he thought he was doing the right thing, and of course he was saving people. Unlike Cam, he's never wanted to leave hunting behind him. He's likely come to Freedom Falls hunting some supernatural or trying to find Cam.
His exact age and playby are both open, as is his first and middle names. There's a few more details about their family in Cam's app but the important stuff is all mentioned here. I'm pretty open with how this goes. though I'd prefer that he's an active hunter, with no current intentions of leaving the life. That can always change down the road but I kind of like the idea of Cam trying to convince him that supernaturals are normal people just like they are. Marcus could also have been turned, maybe thinks Cam would hunt him if they met, for some extra family drama.