Like, I honestly thought he was pretty normal until I played through the ending of day 2 and day 3. I played with two "mini-routes", one where mc tells mikko he's jealous and the one where he tries to get mikko apologies from torulf, and playing through them kinda made me realize that I'm kind of wrong in the head for taking half of torulf's behavior as normal, and that he kind of gives me creeps. Like, I honestly want to keep playing his route but I'll keep going because Im truly interested in what ends up happening in the end of both mini-routes and what does he actually feels about that whole messed up situation with Lake and the mc
This is one of the reasons why the author is amazing... I think they kind of put you into Arvo's perspective so well that you don't really notice how isolated from your friends you've become until it's too late. You get pitted against Lake and against Mikko and against everyone because he wants to test how far you're willing to go for him.
Torulf is kind of toxic because he's driven on a base level by a desire for recognition due to—from my perspective at least—a lack of confidence in his own self worth. He seeks external validation to feel as though he means something. We see this in the way he preens in front of others, and his openly flirtatious attitude. We see this in his actions towards the MC and towards lake.
However his desire for external gratification melds with his fear of commitment and creates this really unhealthy balance of push and pull on people's feelings.
Look at Lake, for example. On the one hand, Torulf desires to be close to him physically and maybe even emotionally in some deep hidden way. He loves the attention and the compliments. He loves to be desired, but when the sex is over, and the cuddling is past... when the gradification ends... he's left empty again, and because he can't fill himself up with his own confidence and his own love, he goes out to seek it from others once again.
This creates a poisonous cycle of distancing himself and getting close and distancing himself and getting close. Hot and cold if you will.
If you haven't yet played Lakes route yet, I would do so. If I'm correct you get a glimpse into Torulfs mind near the end of the newest update. I shall leave it at that. Hopefully my ramblings make sense.
Torluf(and us by choosing his route) breaks Arvo on a fundamental level. We choose that Arvo "feels comfortable" with Torluf's flirting, but based on the little knowledge that we know ABOUT Arvo, his personality, and past, would he ACTUALLY be okay with it?
If we step out of our "We control the main character" point of view, and look at the situation through, say Lake's or Mikko's perspective, we would probably see some stranger changing your friend from Mikko's view, and a person who you seek validation from(Via compliments, contact, or sex,) pitting your friend against you from Lake's view.
The bathroom scene after the third NSFW scene shows Arvo(almost) realizing what's happening, and getting disgusted by himself and his actions(At least, that's how I interpret it.) He also confides in the ram lady who's name I forgot about it, and seeks advice from her.
It's also important to note that this doesn't happen in ANY other routes. Not after anything with Bjorn, not after anything with Rune, not after anything with Jorgen. It's only in TORLUF'S route. I may be copying what someone has already said, but the other routes bring out different parts of Arvo's personality, while Torluf's route changes Arvo into doing things that he probably wouldn't do on any other route.