He has been related to basically everything, Tequila, Suguru Itakura, Vermouth, FBI, Kir, Bourbon, Haneda Kohji murder case. They just don't want him "snooping around" anymore.
Edit: Also, Miyano Akemi.
How?
So what? Do they get together or no? It feels like they did but I can not be 100% sure. I feel like the proposal was really subtle or foreshadowed. I don't really get these things, but I am glad the manga ended on a positive note. Thanks for your work, Irregular Scans and Orion Scans. And thanks...
He never over-estimated or under-estimated anyone. The main reasons of his defeats were the non-participation of the royal army, and the accepting of refugees on the Earl's part.