Bolaire Is Not Remorseless
I have seen many posts describing Bolaire as a "remorseless serial killer." For a start, I don't think Bolaire is a serial killer any more than a Cordyceps fungus is a serial killer. Taking over people's bodies is simply a matter of survival, not of sadism or thrill. Of course, unlike a Cordyceps fungus, Bolaire is capable of moral reasoning, which brings me to my main point: just because Bolaire never says out loud "I feel guilt about my means of survival" doesn't mean he doesn't feel any guilt about it.
I point this out not to excuse Bolaire's actions or let him off the hook. Rather, I want to talk about Bolaire's guilt because it provides an opportunity for character development down the line. If he didn't feel any guilt or shame about his current lifestyle, it'd be pretty hard for him to have an arc about it.
Because Bolaire doesn't clearly articulate his feelings of guilt, we're going to need to do some analysis of the text. Let's dive in.
Castep is the name of Bolaire's host in the episode 13 cold open. He was a soldier in the Falconer's Rebellion, and he chose to wear Bolaire in order to contribute to the war effort.
At the beginning of this flashback, Bolaire is subservient to Castep and to the other soldiers, obeying whatever they ask of him and responding honestly to all queries. It is important to point out here that it is not in Bolaire's nature to be subservient. First off, it would be pretty weird to inscribe a rune that compels and enchants people into a mask that is meant to be subservient. Second, according to Taliesin's comments in his interview with The Character Sheet, Bolaire's programming consists of two directives: defeat tyrants and love his siblings. In the Tale Gate for the Schemers, Taliesin said that Bolaire's character was an intellectual, and a cross between Elle Woods and Regina George: a mean girl rules lawyer. None of this points toward Bolaire having any subservience in him to begin with. All of this means that Bolaire either decided on his own to bend his will to the rebel soldiers who wore him, or he had subservience beaten into him, perhaps with the threat of putting him in a box, a possibility that clearly frightened him in the flashback.
When Bolaire did decide in the flashback that he was going to take over Castep's body permanently, he didn't just say "I'm sorry"; he also promised to Castep that in exchange for his bodily autonomy, he would fight out the rest of the war that Castep put his life on the line, and willingly wore Bolaire, to win. I really don't see why Bolaire would bother fighting for two more years of a war that he clearly didn't want to fight anymore (he was tired, so tired, and wanted to be something new) unless it was to assuage his own guilt for what he'd done to Castep. I think this view is reinforced by the fact that Bolaire's preferred human disguise in the present day is Castep. He feels haunted by this soldier who shared his belief in defeating tyrants, whose life he stole away.
In the play from the flashback, Rauwyn puts Sir Clynheld through a series of trials to prove his worth. Bolaire clearly took this to heart, because in the present day, he has only taken hosts that have failed his moral standards. (Again, I am not justifying this behavior, and I am not saying his victims deserve what they get; I'm just describing what I observe Bolaire doing.)
Let's consider Bolaire body-snatching Aubrus Drime in episode 4. Bolaire set up a rather elaborate scenario. He told Drime in advance to bring payment, because he had a cool magical artifact for him. He then showed up an exchanged an empty box for the money. Drime responded by attacking Bolaire, stealing him ("his mask") off his previous host, and clearly would have killed the previous host were they not already mostly dead ("Well, won't even have to kill ya. Looks like you're on death's door.") Drime then saw the rune and was compelled to put Bolaire on.
Now let's think for a second. This is a very inefficient way to get a new host. If Bolaire truly did not give a flying fuck about morality or anything, he has the spell Suggestion; he could just enchant someone into putting him on. Even if he were out of spell slots, there are much simpler ways to get someone to put him on, with a higher probability of success. Off the top of my head, he could go to a doctor and say, "Hey doc, I wear this mask to cover up an old injury of mine, can you check on my old injury?" and BAM, doctor gets nabbed. Hell, Bolaire has money. He could just find someone poor and desperate and pay them to put him on. So why did Bolaire go through all this rigmarole?
It's because this was a test for Drime. It was a morality trial, like the trials in the play about Rauwyn. Drime could have handled the situation in any number of ways. He could have asked Bolaire why the box was empty and tried to negotiate or reason with him. He could have taken the money back and told everyone in Potter's Field that Bolaire was a cheat and they shouldn't make deals with him. He could have threatened Bolaire and demanded that he take Drime to his stash of magic goods. Drime didn't do any of those things. Instead, he chose to attack and steal, and would have killed, if Bolaire's previous host hadn't already been mostly dead. By Bolaire's standards, Drime earned his fate: he made the immoral choice, and now the monster got him.
Now let's fast-forward to episode 22, and the Crow Keeper who Bolaire body-snatched with Hal's assistance. Bolaire didn't need to morality test that Crow Keeper, because he already knew what he'd done: he and his fellows had kidnapped and beaten Demodus Blix to within an inch of his life, and were about to sell him to a mold monster.
I think it's pretty clear that Bolaire in the present day is only willing to take over the bodies of people who he feels have earned that fate. In the case of Aubrus Drime, he went to pretty convoluted lengths to make sure that Aubrus would only succumb to him if he chose violent theft. Why would Bolaire go to all that trouble if he didn't feel any guilt at all about what he does to his hosts?
Bolaire clearly feels dysmorphic about his host bodies:
"This is me, unfortunately stuck to this. I need this, but I'm not in here." (episode 4)
Why does Bolaire feel that it's so unfortunate that he's stuck to his host body? He is a humanoid face, after all, not too different from the face underneath him. He was made to wear a being with a humanoid body plan; it seems doubtful that he could wear a Hound of the King or something like that. It's by no means a given that he would feel that this was unfortunate. I put it to you that at least part of the reason he doesn't like wearing host bodies is the guilt.
In episode 20, after Murray and Bolaire were done planting a terrifying illusion in Groto's head, they had this exchange:
Murray: "I feel a little guilty. Let's get back to Hal."
Bolaire: "Guilt is the best part."
I don't think Bolaire was being flippant here. He meant it. He does feel guilt, and the reason why he thinks that guilt is the best part is that only someone with free will can meaningfully feel guilt. If you are completely subservient to others and take no actions of your own accord, the way Bolaire used to live, then there's no reason to feel guilt, because you have no responsibility for any of your actions.
Y'all, Bolaire's offer to Hal to come see how his body snatching works is not given in the spirit of a mask who feels no guilt or shame about it. It's really, really not.
"It doesn't have to be you, but it is an imperative that I ask you first because I owe it to you. I don't think it's healthy and I don't think you'll like it, but it is not a secret I am-- It's not a secret I can keep from you. If you want to see the worst of me, you can wait." (episode 22)
And take a look at Bolaire's face while he's explaining to Hal what's about to happen:
How Bolaire treats his hosts
The most common argument that I see for why Bolaire is "remorseless" is the way he treats his hosts. Clearly, he does not treat them well. He could try his best to keep them comfortable and well-maintained and so forth, but he doesn't. But here's the thing: I've lived enough in this fucked-up world to know that just because someone feels guilt about how they are treating you does not necessarily mean that they are going to treat you better than someone who doesn't feel any guilt about mistreating you.