I am in confusion

I've reread this maybe 4 times and there's still so much I don't understand. Either I am too dumb and need things spelled out, or they were never explained. Who the hek is Edwin? Why was his aim Ryan? Why did they plant ppl in two different houses if Ryan was their main goal? Why did Ryan's sis work on developing a solution that could kill her own brother? And probably herself or even her parents if she was a half? What was Ryan's motivation for helping his sister develop it, was he just found of his sis or was there ”more” to his feelings? Why did his sis want him to get married to Cecilia? Why did Ryan not even attempt to make an antidote himself? Did he actually know another antidote and is that how he was able to save Lucaon? How come nearly every royal had a complete personality change during the story? So many plot holes.. feels like they kinda gave up on the plot and wanted it to end as quickly as possible..