Michael-Scott Earle has a real talent for characters. Oh his world and story are both fun and engaging, but I've read a lot of stories where both those are true as well. No, what really sets these stories apart are the variety of unique, engaging, and multidimensional characters, both in and out of the game.
On top of the interesting world he's created (in and out of the game) the mystery from the first story is continued here, cryptic hints keep being dropped, and while I have suspicions about various things, I'm still left theorizing possible meanings, which I love. All and all, this is one of the best LitRPG's I've read, I can't wait for the next one.