As much as I like the novel, I gotta say, the mc at times behaves like a robot of sorts. I peg his lone-ness to the fact that he has to be singleminded in the pursuit of those that harmed his brother. He won't get easily attached since anyone could turn out to be his enemy the next they meet.
Still, it can't help but leave me as a reader feeling something is lacking. A sense of emptiness if the OP nature is set aside 😧.