From Mognet's @Ikkin, whew:
1) FFXV’s trend of highlighting Noct’s vulnerability clearly remains in full effect in the Omen trailer. In this case, though, there’s a conscious effort to show him being stripped – most obviously of his clothes, but also his powers and his mind. Without his friends, the trailer seems to say, Noct is easy prey for the black dog.
2) The black dog is not Umbra – Umbra appears as Pryna’s reflection, likely represents Noct, and looks different from the black dog. Rather, the black dog is likely meant to be taken as a hellhound; it clearly reflects some of the requisite mythological baggage. The black dog has glowing red eyes, it’s a herald of death, and it’s shown three times in Pryna’s place (some of the hellhound myths say that it takes three sightings for its curse to take effect).
Character-wise, I suspect that the black dog represents Ardyn, who’s already been shown to be a false ally turned traitor and whose black wing-cape-thingy aligns him with FFXV’s take on Reapers. As such, it seems like the dynamic in the game will have to be different – Noct’s friends can keep him from being led astray unknowingly.
3) While Noct’s friends clearly change the underlying dynamic, I don’t think we’re meant to see the events of the Omen trailer as wholly hypothetical. There are a number of references to scenes we know are going to happen in the game, after all – the invasion of Altissia, most obviously, but also the fights at the train station and in the Niflheim base, and the way Noct’s trip takes him through the Coernix gas station.
As such, I suspect that the fights that we haven’t seen in previous trailers will likewise appear, if in a different form. There’s nothing particularly unbelievable about Noct and co. facing off against a Behemoth in a palace or Niflheim soldiers on a railway bridge, after all. Fighting Luna would be the most questionable if it weren’t the very thing that we’re supposed to be trying to prevent. Changing fate always happens at the eleventh hour in fiction, regardless of any and all previous attempts; if keeping Noct from falling to madness and killing Luna is the goal, then it has to happen during that fight.
(It’s worth noting that Amy Shiels, Luna’s VA, said that there were a ton of action sequences towards the end of recording, which is consistent with this prediction.)
4) Of course, if the dynamic is different, there’s gotta be a reason for the climactic event to take place anyway. And, in this case, I think that reason has already been hinted – if Ardyn can’t lead Noct astray unknowingly, he can always just imprison him in the Crystal and torture him into it.
This is where things seem to give off heavy Avatar vibes. Ardyn needs Noct to become the True King to consider Noct’s death satisfying, which reminds me of nothing quite so much as Zaheer’s plot to kill Korra in the Avatar State. We don’t know what Noct’s “True King” form looks like, but the uncontrollable daemonic-looking version of Noct that killed Luna in the vision certainly seems like it could fit the bill.
Unlike the Avatar State, the daemonic-looking version of Noct appears to be a being of darkness and chaos rather than of light and harmony. But if some of the underlying FNC mythos has stuck around, that… actually sort of makes sense? Chaos in FNC is what gives humans free will, and thus the ability to fight their fate. It’s entirely plausible that a properly-controlled being powered by Chaos could be required to deal with the Plague of the Stars in place of the gods. (Or maybe the King of Light functions as a sin eater, taking chaos upon himself to remove it from the world? A lot of people die in the XV canon, and that'd mean a lot of free chaos by FNC rules. And there could be an association between light and chaos, given Noct's ability to see the "light of expiring souls.") Of course, without proper control, such a being would just be a monster, and without proper context, it’d be easy to think that vanquishing the “True King” and the Chaos it represents would restore the world’s balance as opposed to ensuring its doom.
“There’s nothing either good or bad but thinking makes it so.” Perhaps this is what that means – the “evil” powers that cause Noct and Luna so much pain in the vision can actually be used for good, given the proper mindset.
4a) If the “True King” is Noct’s Superpowered Evil Side, what if he’s the one to blind Ignis and scar Gladio, and that’s the reason why Gladio is so upset at him in the train?
4b) It’s a rather odd coincidence that the tree Noct sees the false Pryna under and ends up fighting Luna near looks rather like the Tree of Time from Legend of Korra, given the other similarities. XD;
5) If the vision is what we’re trying to prevent, it’d be awfully strange for Noct to outright fail to do so. However, the ESRB synopsis references scenes that sound like a perfect analog for what we saw in the Omen trailer: “one cutscene involves a woman being stabbed off-screen; another scene depicts a character with a bloodstained wound.”
One explanation, of course, is that the vision – or, at least, the portions involving Noct and Luna’s fight – is actually reproduced in the game. If the game is actually building up to a final confrontation that will determine whether or not the vision will be averted, it’d be awfully strange to leave that vision out of the game itself. Maybe Noct has nightmares about it, or he sees it when an Astral is messing with his head. If that’s the case, the ESRB synopsis really doesn’t predict anything.
The other option is that Noct actually does stab Luna, but things change after that because his friends are there. She wouldn’t even need to die, necessarily; Prompto and Gladio could hold Noct off while Ignis keeps her from bleeding out.
6) I’ve seen a lot of talk about how the Omen trailer basically proves that the Ring of the Lucii is a bad, bad thing, but Noct doesn’t actually wear it at any point in the trailer. That he does get it in the game is a point of differentiation, not a step down the dark path shown in the trailer.
7) The trailer obviously wants us to assume that the one death that the voice speaking to Regis is looking forward to is Luna’s, but that seems almost too obvious. Besides, whether the voice is the Crystal or one of the Lucii, it’s unclear why Luna’s death would allow it to rest. I’m more inclined to think that it’s looking forward to Noct’s death, probably to put an end to the line of Lucis and free the past kings from their duty.
Regis, of course, can’t let that happen for a number of reasons. And so, he chooses to defy fate at Insomnia’s expense, asks forgiveness from the gods for the carnage he knows will ensue, and walks knowingly to his death.
