The "butcher of the Armenians" or "monster" and "madman" (as Vahan calls him) gives Vahan a place to stay after he's worn out his welcome with the Altoonians (17.6). Vahan struggles with the idea of accepting things from Selim when he knows what the guy is capable of. He says:
At first I wanted no part of his generosity. I wanted only to be left alone, to eat and sleep and survive until it was safe for me to return to the Altoonians'. I was still an Armenian, after all, and he was still the enemy. (18.30)
There's no denying Vahan has a more comfortable life with Selim Bey than in Goyran's Inn, but he just can't feel at home with the guy. Perhaps it's because he knows Selim Bey is off killing people left and right for no reason, or maybe it's because he feels guilty about his family dying or being help captive. Either way, it's clear that home isn't a building, but a feeling for Vahan.
It's not just a place to stay and a warm meal that Selim gives Vahan either. He's also always offering Vahan advice, like:
"[…] there is no such thing as a country or a flag or a right or wrong cause. There is only yourself. You are your own flag, your own cause and country. In the end, if you are poor and cold and hungry, no one will care if you were a patriot, or an honest man. All they will see is a beggar, an unsuccessful animal. Do you understand?" (18.32)
What's telling is that his advice basically comes down to every man for himself. Given the fact that he's killing people for no reason, this might not surprise us, but it is interesting that his message isn't something bad about Armenians specifically—it's about making your own way in the world, and defending that path from anyone who gets in your way.
If we didn't know how many atrocities Selim himself is associated with, we might even think that this is advice that comes from someone who's experienced intense violence himself. These are certainly the words of someone who has some trust issues, that's for sure—but maybe that's just because he knows how unreliable people can be since he's, you know, pretty unreliable himself.
Check out this other gem of advice Selim shares:
"Pick your friends carefully and protect them if you can," he said. "Leave the rest to their fate." (20.39)
Yup—Selim definitely thinks the good ones are few and far between, and also that there's no need to just help people out for the sake of it. So when Vahan asks about Seranoush, the governor's response is worse than Vahan ever could have imagined—Selim makes it clear to Vahan that he has no control over what happens to Seranoush or anyone else for that matter. In fact, Vahan probably shouldn't even worry his pretty little head about the girl. Ugh.
After a while, Vahan finds himself second-guessing everything he knows—or he thinks he knows—about Selim Bey. He goes from thinking the guy's a monster, to actually liking him, to hating his guts. It's clear to us that this is not so much about what Selim does to Vahan, as it is about who he pretends to be.
Remember when Vahan first meets the guy, and he's impressed with how nice Selim's clothes are, and how respectable he is? Well that all changes—as Vahan reflects on it he says, "only later did I realize how inhuman a well-dressed, well-spoken, charming man could be" (18.35). Vahan realizes that it's not about how Selim presents himself that matters, it's all about what's underneath those fancy clothes… which is a cold-blooded murderer and rapist. No amount of designer clothes or swagger can cover that up—Selim is a wolf in sheep's clothing.