tl;dr, Rilien is cunning, manipulative, quick-witted, social, energetic, 16 year old idiot who is scared of having to come to terms that he actually doesn't have any magical abilities.
As a Fortune Teller who makes money from lying and manipulation, Rilien is very cunning, quick-witted, but inevitably has an underlying childish demeanour. Rilien is, importantly, still a boy, and can be quite innocent and oblivious to some things, but brash and almost crude with others. He has the '16-year-old boy sense of humour', meaning mischievous, sometimes dirty jokes that only a 16 year old would find hilarious (they're not) He is the type of boy with a fear of boredom and loneliness, and in some ways, a calm and peaceful life, constantly finding a way to not feel like he is withering in his own unceasing energy. That is also the cause of Rilien's infatuation with human interaction, whether for
scamming business, or simply becoming friends with people who have the ability to tolerate him.
He is very well aware that his powers as a Seer are practically non-existent, and he knows he is a fraud. As it is a potentially touchy subject, a part of him believes that without it, he may be not worth much as a person at all. He hence feels a sense of accomplishment when he is able to scam people he deems successful, capable, or even merely better than he is, despite the victory being somewhat cruel in its nature. A part of him realises that he is cowardly and perhaps, to put it bluntly, pathetic, though continues to hide it with the victories he believes makes him happy.