QFT. In fact, I think Lauriam is more in character here than he has been in the whole story so far. As I said, him hitting Ephemer does feel wrong, but that is based more on my headcanon than on anything we have seen on screen.
It is an exceptional situation either way. Lauriam hitting/attacking Ephemer, Brain and Ven is
technically all wrong when taken as actions by themselves, but given the circumstances they're understandable to a degree and, I think, forgivable.
Also when looking at the fact that both Skuld and Ephemer intervene before any damage that possibly can't be remedied is done.
Brain also lives up to his name again by immediately deducing that "Darkness" wants them to quarrel and strike against each other.
Classical divide-and-conquer strategy and by now I am almost sure "Darkness" also had a hand in making the quarrels among the Foretellers worse somehow.
Ven blaming himself despite not actually being the murderer, heck not even lifting a hand, is also so painfully in-character. I'm just waiting now for a re-enactment of the first meeting at the Keyblade Graveyard in BBS where he asked Terra and Aqua to "put an end to him", only this time with the other Union Leaders.
I'm quite worried about this possibility, because it would almost automatically mean that the story, or at least the murder mystery and its solution part of it, is poorly written and bad. It was supposed to be about MoM's unneeded secrecy and the foretellers' stupidity, not some unknown third party.
Not necessarily. There being multiple "Darknesses" was a realistic possibility from the start.
I remember from the very first main story quests of the original Browser Chi that Chirithy mentioned there being several "Seekers of Darkness" posing as Keyblade Wielders (dunno if that part was taken over into Unchained/Union X), there was one scene imagined by Player with nine black coats standing against thirteen on the Keyblade Graveyard and there's also the possibility of multiple Dark Chirithys.
Do we actually know for a fact that the story is "supposedly" about the MoM's unneeded secrecy and the "stupidity" of the Foretellers though?
The mysteries behind the story of the original Browser Chi/The Foretellers and the actual reasons for the whole chain of events leading to the war, including the "traitor", were never made fully clear to begin with.
The "murder mystery" might actually be just one part of the overall plan of the "Darknesses", even Brain's assumption that it was done "just" to disrupt the connections between the Union Leaders and shatter their unity so that they can be dealt with easier is a plausible explanation.