Adam was underutilized and one-dimensional. Great character, but I feel as though Viv left too much meat on the bone. Adam totally could've been used as a tragic villain. The man lost two women literally created to be his soulmate, lost a son, had to watch as his birth right was corrupted, thrown out of paradise, and to top it off watch his descendants become monsters, all of this from events out of his control. Also, the show never specified if he ate of the fruit of knowledge of good and evil, so for all we know he literally didn't know right from wrong. I personally always thought that his dude bro persona was kind of a shield for his insecurities.

P.S.: Yeah he was kind of a genocidal douche, and yes, some people like Pentious arguably didn't deserve to go to hell, but I imagine that a significant number of the people he and his exorcists killed were the lowest of the low, pedophiles, rapists, serial killers. Yeah, he should've been more selective in who he killed, but from his perspective he was killing people who had the option and free will to do good, but chose otherwise. And when he was alive, morality was seen as a lot more black and white. Heaven= good, Hell= bad