Blackthorne

This is secondary-world military fantasy, with complex and detailed worldbuilding. The titular is an escaped killing machine, now trying to decide how much of his psychological indoctrination he can discard, and what he will replace it with. It's the second part of a series, so I'm not sure how much of it would be comprehensible without the first book (Cold Iron), but if you've got the time and inclination for a couple big meaty books, these would be a good choice.