Well, if I make a thread about "your fav main chracter" I'm pretty sure it'll by flooded with GJ, YG, XF etc...so let's shrink it down to the protagonists of the less famous novels.
I personally like Di Yun from A Deadly Secret the most, he was an innocent farm boy (unlike the tricky YG) and has the worse experience ever for having his fingers sliced off and bone penetrated (yeah even worse than those of YG's) without being emo with. Di Yun's childhood crush also married to the guy who perpetrated his imprisonment. His character development was great from being an innocent farm boy, to a victim who gets to taste the ugliness of humanity when he got imprisoned in a city, and finally a hero who doesn't want to get into a mess