Blizzard artists are usually good at having an attention to detail. If you'll notice, all the towers and stone structures are leaning away from where Jaina's tower used to be and the debris patten indicates the material being spread outward from that location as well. Based on that, and the glowing crater with crackling energy, points towards the tower exploding or something explosive striking the tower (obviously something magic). The damage seems less severe the farther you get away from the tower, however...mostly a burning roof here and there.

If Jaina blew up the tower in desperation, you would figure that there would be a strong indication of damage in the structures farther away from the tower, including those that did not have a direct line of sight of it. You'll also notice that the 2 steamtanks by one of the gates seem just fine and dandy. If there was a prolonged siege of the city and Jaina was doing the self-destruct thing in desperation, you'd figure that all the defensive ordinance would be destroyed. Basically the thinking is that the city has been breached, the army shattered, and her only hope is to go nuclear?

That doesn't seem to fit.

There are a large number of graves, and some of the graves (like the one with a doll) suggests children were killed as well. We can assume that a blood thirsty Garrosh wouldn't give two damns about giving people a proper burial. Half the city seemed more or less ok, while the other half was not, so I assume the graves are for the unfortunate half and they were buried by their own. If the city was under siege, it's pretty much in Jaina's character that she would try to evacuate the civilians if possible. Everything seems to point to a sudden and decisive strike. From that brief video, you don't see the signs of a prolonged siege or military attack, which suggests that no one was expecting it and there was no time to actually make preparations for it (be it defense or evacuation).

My theory: Somehow, Garrosh found a way to turn Jaina's tower into a weapon against the city. Since the explosion seems arcane in nature, my guess would be it was kind of like overloading a battery. By the time Jaina realized what was happening, it was too late to do anything about it. With very little time to act, she tried to enact some type of spell to protect what she could. The resulting arcane explosion + interaction with her (mages are basically conduits for arcane energy, when you get down to it) basically acts as a "short circuit" (or maybe she acts like a circuit breaker, if you will), but the net result is Jaina seriously frying her mind and causing physical damage to herself (white hair?).

Honestly I think that scenario makes the most sense based on what we have seen so far in the video and what the devs hinted at in terms of the ultimate fate of Jaina + Theramoore.

Jaina going nuclear, even if the city was overwhelmed, still makes no sense. I mean, Blizzard -COULD- have her do that, but it would be another "lolore" moment that is just crappy writing. She's a tactical thinker and there is nothing there to suggest there was any manner of intense military campaign from the Horde.

I suppose we will find out in a few months.

The only thing this reminded me of was Dalaran. I am surprise no one else thought of this. Granted, Dalaran was vastly different. We do also know Jaina has the power to mass teleport, she's used it on several occasions (though, I suddenly wonder what she didn't mass teleport us in ICC-5 when Arthas was chasing us).

Anyways, back to topic at present hand. She's calm. Cautious. Rational. We need to think of something that would make her snap. Something that would change her personality.

This might be going a little bit "out there" but what if Jaina was possessed? Or a demon of some sort was in control of her? This wouldn't be the first time we've seen this kind of thing in lore.

It looks like that is the only way Blizzard can make someone "evil". Another possibility is that maybe some magic just went haywire. Not something Jaina casted herself, but probably strong enough to kill all magi that don't have Jaina's magic abilities and it took a sacrifice on her side to even survive it. Maybe they ley lines are involved? I don't think it was something that the Horde intentional tried to do, since it doesn't find their MO when you look at past events.

I can see Jaina doing so in order to make the Horde's win a Pyrrhic Victory. That would make sense at the last moment when the Horde infantry is flooding through to gates and all is lost, she blows up the city, killing a whole lot of Horde, and leave them a burnt crater instead of a conquered city.

This also reminds me of Dragonlance lore. When the common folk were goaded by a religious figure to storm Towers owned by wizards, all the Good/neutral/Evil wizards decided to blow up the towers rather than let the ignorant cause greater harm by messing with arcane artifacts. The after effects were of course similar to what we would expect of a nuclear weapon, killing anyone remotely close to the Towers.

Shattering her confidence and calm might require nothing more than a botched spell.

People don't see Jaina going nuclear. What if she didn't think it was going to be nuclear? She thinks she's found the solution to the siege, she think she can handle it against the horde's arcane casters (who, knowing they have this level of power to face, are in force and countering her every move). She goes, it doesn't work that well, and in the end, she can only save herself, and the rest of Theramore is devastated. By her own hand.

Massive PTSD incoming.

Very curious to see how it all plays out, I liked her being the voice of reason in spite of all the insanity that has happened to her. Garrosh decimating Theramore's population and then her retaliating with nothing to lose would be my guess.

Pure speculation here: What if she tried to teleport whole Theramore out of the siege like the mages of Dalaran did with their city? I guess it is a fairly complex and demanding spell, something which takes a lot of focus and energy. She might have been disrupted or some siege engine projectile hit the tower while the spell was being cast and it backfired. But yeah, we'll have to wait and see.

The white haired model now looks like it was an April Fools joke.

New Jaina Model mmo-champ

MMO Champion made the model as a joke, but her hair is turning white.

Looks like a Buru re-skin to me. I'm guessing the mantids just have domesticated various large insects. from what we know, admittedly limited, about the Mantids, they seem independent of any Old God influence. We have a friendly faction, and the end boss for the Mantid raid is possessed by the Sha of Fear, which for some reason makes he think the designers have been reading Green Lantern too much.