There is one reason why the killer couldn't infiltrate the group themselves: there are already a union leader (let's stick with Skuld). They don't want to rock the boat too much so need a replacement for their murdered colleague.
Right, but if the killer really knew THAT much about who was supposed to have what, surely they also should've known about Ava's note (something she got from the MoM) detailing who the chosen leaders are. Regardless of whether or not Strelitzia was replaced, they were bound
to find out the truth as soon as Blaine decided to read through that book. It's not like Ven being there really delayed that in any way, right? He and Skuld have been neither a hindrance, nor an assistance to unraveling the fate of Strelitzia (if one of them was really responsible they should've taken more steps to prevent the truth from coming to light, instead of messing around building snowmen).
I agree picking Ven is unlikely to just be random and I like your logic above but you start off with the assumption that the killer would want a competent replacement who could pass for a chosen leader and not be caught. Now if the killer were aligned with Darkness, would they necessarily want this?
In fact, having a replacement who is both not well-suited to leadership and is filled with self-doubt and then having them exposed could be advantageous. It sows division within the union leaders and increases the self-doubt within Ventus. And that could weaken Ventus' heart (like Buzz Lightyear), giving Darkness a way into his heart.
Hah.... You've got an interesting point there. Not the sowing distrust part (since that obviously didn't happen), but the idea that Ventus' self doubt could open the door for darkness to enter his heart is surprisingly plausible. Even though I'm not a fan of the concept, an idea like this would explain why "Darkness" was seemingly inside Ven's heart during ReMind.
Well I guess you could think about the butterfly effect in this case. Strelitzia's absence directly lead Lauriam to go searching for her, and that his been his main objective ever since becoming a Union Leader. If she was around still, his course of actions would have been very different. It's too soon to say yet, but I feel like Strelitizia's death was somehow predetermined to happen by the future the MoM foresaw and he did what he did purposefully to ensure that events would play out as they have.
Guess it depends on if Lauriam's efforts to find his sister lead to something game changing or not. So far, his own personal search hasn't gotten him anywhere (Ephemer and Blaine have peiced together more than him at this point). I'm not sure how MoM could've known about Strelitzia's demise, since he wasn't there to witness it, and there's no indication that even Luxu was aware about what exactly
happened to her (and he was the one holding the gazing eye). But I guess we won't know until we see how things pan out a bit further.
At the very least, it could be a trick as a way of causing distrust in the new Union Leaders. The old ones were clearly very suspicious of each other, and maybe the forces at work are trying to repeat that mistake in these new ones. A lack of trust and commune can lead to darkness growing.
Honestly, I don't see there being any kind of mistrust or suspicion among this group when Ephemer (their leader) went out of his way
to tell Blaine that, since Ven clearly didn't know about the switch, he wants everyone to continue working together and solve the mysteries surrounding them just like they were before. Only now they also need to figure out why Ven's here too, if he wasn't chosen.
In other words, what the writers are trying to tell us is that things will go back to buissness as usual until something else
happens to kickstart their plot again. I mean... Perhaps Lauriam
could be distrustful of Ven at first, but he's also been known to fully submit to Ephemer's judgement in the past. So it's just as likely he'd take his leader's word for it and point his suspicion elsewhere. And even if he didn't, it's not like Ven (being as passive and oblivious as he's been shown) could ever do anything to arouse further suspicion anyway.
Also, from the meta, it'd be incredibly trite and unfulfilling of them to pull the whole "there's a traitor, but it's not really any of us" storyline again. I'd really rather we not
have a repeat of Back Cover. Unless there actually is a traitor within the group
this time, I'd say they're better off taking the conflict somewhere else (hopefully something new and refreshing... Not that I care much for Ux anyway, lol).