#and I don't easily see a scenario where he keeps working for Erzsebet in some fashion that gives him a happy ending

[fallloverfic]

I think there's a non-zero possibility he could keep working for her,

potentially to try taking her down from the inside again/survival (assuming she didn't see what he did/didn't take it as a betrayal, but I don't think he trusts that), but that's it. As other folks have mentioned, he hates her too much as the like embodiment of colonialism and treating him like a pet. It's really obvious in the bowing scene in episode 7 where they interact, after which Olrox almost immediately brings the book to Richter + Co. (timing is a bit wonky, but he acts pretty quickly after that, and from my looking back, it's the same evening, so not much time seemingly passed between his confronting Erzsebet and going to give Richter + Co. the book to help take her down, even though he kept the book to himself for a while before that).

It's also possible the creative team will figure out some other reason for him to work for her, like maybe she uses a spell to keep him at her side or something (she hasn't yet, but maybe she felt threats/promises/obedience based on worship were enough; I imagine she also just assumes he's a servant and will follow her because [rich people logic]). Given Mizrak's intent to keep fighting her, it's possible she captures him to ensure Olrox's good behavior. Like I'm relatively certain Drolta knew something about Olrox being into Mizrak on some level, or had a suspicion he had an attachment in Machecoul:

In episode 5, after Olrox says he likes the inn for being quiet, Drolta replies, with a smirk, "Private?"

In episode 7 she says, to Olrox, "Everyone has a weakness. Priests. Dragons."

If she didn't know it was Mizrak, I feel like she'd have assumed it was someone else, and she'd have told Erzsebet about it. Even if Erzsebet didn't precisely see what happened in the abbey as Olrox saving Mizrak, she saw Mizrak moving to attack, and she likely guessed who grabbed him, even if she might not have known why, and could connect some dots of "this might be useful." Heck, if nothing else, he might stay connected to her to ensure he's there when Mizrak comes back to fight her again and so Olrox can deflect attacks from him that way.

But honestly, if Olrox doesn't join the main team, or maybe stick to his own self and maybe help a little from the sidelines (I mean Richter has a very big Reason to Kill him, and Alucard might side with him about it, so he's got a big reason NOT to join them besides not wanting to be around Mizrak after their fight), I think he'll figure out a way to go home somehow. Just all out leave. In a way that's what I'm almost more afraid of because at least if he stuck around, even for a bad reason, he'd be in the show, and if he leaves, I think he's out of the show (and I just want more of him T-T). But him hearing what Mizrak said and being like "yeah, fuck this" and just peacing out makes a lot more sense than anything else to me, even partnering up with Alucard and the rest. (Of course I'm also afraid he's gonna die, particularly if he pretends to keep being on Erzsebet's side, so I'm hoping that doesn't happen T-T).

The only things I think that might stop him from just leaving Europe entirely somehow is how Erzsebet's spell is fucking with naval navigation so boats can't travel and/or her followers ate all the sailors. Unless he just wants to idk flee the country by land, he needs a boat to get home. He could maybe go to another port outside the area, I guess.

I don't personally see Mizrak's words hardening his heart enough to make him side with Erzsebet. He's quiet, he watches, he's self-interested, and he really doesn't seem to care about power and conquering, and I don't think his past lover or Mizrak did or could change that. As he notes to Drolta by the graveyard, he likes to keep his ear to the ground. He also has nothing to gain by siding with her (I mean if he wanted to kill/torture Mizrak, he could do that already, same with Richter). He doesn't prioritize going after Richter, and likes eating rich people, who are Erzsebet's main allies. Also while Erzsebet can have more than one lieutenant, I think that spot will be held by Tera, not Olrox. And he'd hate that from so many angles even more than pretending to worship her briefly.

I've seen a lot of people speculate that Olrox will keep helping the protags and maybe even join the mc group in season 2 but I have not seen anyone wondering if he'll actually just keep working for Erzsebet. and maybe even become a new Drolta or something. like what if Mizrak's cruelty hardened his heart. what if he just goes full evil