What excuse does a sociopathic leader of a secret society have pretending to be someone's best friend for a vast amount of time? What would he gain? Why hang around for so long if he doesn't care about that person, especially someone of his status? Some may say why bother with such a plot point in the first place but I am trying to work with this idea and mold it into something that will fit and make sense. I like this idea and I don't want to let it go so quickly. But I don't want the idea's elements to come off as stupid and unnecessary. Any suggestions?
If it's a secret society and the other guy is famous in regular society then good social standing, money, new recruits, insider information, maybe a network where he gets things he couldn't otherwise obtain, etc.
Because the friendship 1) boosts the sociopath's ego 2) gives Socio a good cover story, allows him to look legit to normal people 3) allows Socio to laugh behind the friend's back at the great deception 4) gives Socio access to something or something he needs, like money, social connections, or a pretty sibling
Have you looked into sociopaths and what motivates them? I am no expert so I wouldn’t want to say what would work within that logical framework, but if you look into how sociopaths think, then some answers will spring out.