Disclaimer: I am by no means a scientist. I’ve got a background in English and Theatre, but I have quite a few close friends who do have backgrounds in science. A little while back, one of those close friends, thejmpr, who actually edited this post, approached me with the declaration that he’d figured out how spirit vines worked. I tried to explain that they’re not really supposed to make sense, since they’re all spirit-y, but he proceeded to prove me hilariously wrong. The following is an analysis that I was able to put together by extrapolating his logic. In the end, it’s just conjecture, but I had fun writing it and thinking it all out, so I figure it might be a fun read, too.

Spirit Vines are crazy. They’re crazy powerful, crazy big, and crazy plentiful. They’re the plutonium/uranium equivalent of the Avatar universe, but without all those pesky dangers of radiation! And instead of radiation, they grow back! Like really fast. And all the time.

AND EVERYWHERE.



Pictured: ‘Easily-Obtainium’.



Anyone familiar with Cold War politics, deterrence theory and nuclear proliferation most likely caught the parallel with Raiko stating “[Spirit weapons] are already being used!” as justification for the United Republic to have their own.

But that’s a story for another time.

Today, I’d like to talk about how Mako, through no fault of his own, nearly destroyed all of Republic City…and probably the mountain range surrounding it. Sort of. Sounds crazy, right? Well, so are spirit vines.

I’m referring to this scene right here:

Not as much a needs-of-the-many-needs-of-the-few-sacrifice as he thought.

Badass moment for Mako? Absolutely. Was it the best option he had at the time? With the information available, yes. It was also his only option, but we’ll get to that in due time. Mako was not made aware of just how large the explosion spirit vines cause when ‘overloaded’. Bolin, however, knows exactly how that goes.

Well, okay, he didn’t see that explosion, but he certainly saw this:

Now, that’s a pretty big boom, and it also took around ‘enough vines to fill a barrel’. Y’know, like an oil drum or something. Specifically, this much:

Obviously he’d cut them up before shoving them in the barrel, but you get the idea. Logically, chaining more vines together, especially with a bundle that massive, would create an exponentially larger explosion/release of energy, especially since the large generator in the Colossus was made using Foggy Swamp Spirit Vines, which are far more potent than their Republic City counterparts. And they’re compatible when you chain them together!

Y’know, like what happened to Kuvira in the Spirit Wilds.

Not pictured: Future Industries Tower most likely exploding.

Bolin probably forgot about just how big of an explosion Varrick made since he was trying to convince Mako how bad of an idea it was to blow up the vines in the first place. Turned out okay, though. Because it didn’t destroy everything. No, we don’t even get an explosion at all. We get an implosion.



Okay, a relatively small explosion, but then an implosion. Look closely at the Colossus. What part of the torso is actually missing? For all intents and purposes, none of it is! Except for the big sparky generator. You can still see the two halves of that big room on the exposed parts of the mecha-giant.

Where did it go? The Spirit World, of course!

Hold on, I’ll explain, because yeah that’s a pretty crazy claim to make.

Think of a Spirit Vine as a sort of…thin barrier between the material world and the Spirit World. Now, when you turn it ‘on’, by running an electrical current through it, the barrier between the two worlds weakens, and spirit energy is moved from the Spirit World into the material world. They’re not actually generating anything!

They’re conduits.

That means that the explosion isn’t an overload of power generation. It’s more like a pipe bursting. The vine can only sustain so much energy, so when it reaches its limit, it explodes, dumping all of the energy it can into the material world.

Now, that sounds like quite a bit of conjecture, doesn’t it? Even if it makes sense, there’s no way I could have any in-universe evidence to back that up—oh, wait I do!

You might want to grab a snack, ‘cause this is gonna take a bit.

Let’s begin with the ‘explosion’ part.

The best way to do that is to explore both times that Varrick blew up a train car with Spirit Vines. We’ll start with the instance where he did it on purpose. Varrick, in an admittedly smart move, managed to link all of his vine samples together to create one big bomb instead just the one he was using for testing.

The purple means it’s working!

This is distinctly different from the first time that we see him testing the power generation capabilities (to charge a battery) of spirit vines. See how all of the vines are purple in the above shot? Okay, those are, logically, all of his samples taken from that bigger one he snagged during “The Coronation”. However, during the test we’re shown in “Enemy at the Gates”, only the vine with the active electrical current is purple.

…which leads to, uh…

That. But hey! It’s still purple, and the ones in the background aren’t! So that tells us that Varrick’s plan to blow himself up by using all the vines was totally on purpose—

Right. That happens, too. This tells us that there are two distinct ways for spirit vines to be used as weapons. As a death ray and a big ol’ bomb. There’s a third use for them, but we’ll get to that. The more important question is why were these two instances so different? Right before Varrick almost blows up the train, he describes how he’s going to test the spirit vine. Now, some of it may seem like technobabble, but I’d argue that it’s not. Not entirely.

“I have postulated that these spirit vines are a form of pure energy that’s unstable in what we call “typical earth conditions”. This machine should transfer the energy from the vine into a battery using electrical currents, reverse magnetic polarity, and a little-known phenomenon I like to call the Varri-Effect!”



[I’m almost positive that bit about reverse magnetic polarity is just a silly reference to Nuktuk (which actually did have a sequence where the Earth’s polarity was reversed, which somehow brings Juji back to life…?) so we’re just gonna skip over that. It’s also a very common sci-fi trope, like tachyons doing whatever the hell you want them to do.]

Varrick’s assumptions about the vines are, in a sense, correct. They are definitely unstable, but they are not pure energy. They do, however, grant access to pure energy, as I’ve mentioned above. Varrick was actually transferring energy from the Spirit World and into that battery. But, he didn’t know he was pulling energy from across another plane of existence, so it overloaded.

The ‘accidental beam’ of the spirit vines is in actuality the most ‘pure’ form of spiritual energy. It’s not altered by science nor is it controlled in any way. The only thing that Varrick did was more or less plug it into an outlet.

Why?

Because Vaatu.

Vaatu is a lot of things, but for the context of this big post, I’m going to focus on his abilities. He’s got that purple beam, vine generation, and the capability to create spirit portals.

From Beginnings, Part II: “It was I who broke through the divide that separated the plane of spirits from the material world!”

Holy crap. He made the freaking spirit portals! The original ones! From inside the spirit world! That sounds really familiar, though. Purple, lots of energy, breaking through barriers, spirits of absolutes—

Oh.

Oh.

…right, the energy exploded outward, then got sucked back into—

Yup. That’s the third, and surprisingly most-likely-intended use for Spirit Vines!

Or, well specifically that kind of energy.

(I have a running theory that Korra can’t actually close that portal, because it was made with the combined energies of both Raava [Avatar State] and Vaatu [Purple], but that’s a whole other thing.)

I mean, what did you think that Unavaatu was trying to do when he started tossing vines all over Republic City? He wanted the spirits to take over the material world, and the best way to do that is to make more spirit portals. What better place to start than the ‘center of humanity’?

From all of this Vaatu stuff, coupled with what we know so far about spirit vines and how they work, it’s safe to come to the conclusion that Baatar Jr.’s Mecha-Giant Spirit Energy Generator (patent pending) forced the energy to implode into the spirit world.

But that’s only half the puzzle, folks! We know that it did that, but not the reason it didn’t just explode like everything else. To answer that question, we have to go back to Varrick and his vines.

So, Varrick is both Howard Hughes and Oppenheimer in Korra? Oh God.

Varrick never quite figured out how Spirit Vines worked, though this was on purpose. Remember, he tried to blow himself up and explicitly told us that he couldn’t stop the bomb from exploding even if he wanted to. After he and Bolin were already free of Baatar Jr.

So I’m going to trust his word on that.

That bomb he made wasn’t as complicated as you might think. Since he knew that electrical currents cause explosions after a certain amount of time (despite not knowing why) it was a simple matter of doing some quick, and probably sloppy, math to determine how much electrical power he’d need flowing through all the vines in order to have them ‘overload’ in five minutes. He can’t know the timing for sure, so he makes the remote, which, while not actually a detonator, performs a similar function. It most likely maxes out the electrical power being sent to the vines, which would be a ‘shortcut’ to that explosion he wanted.

(That was probably the actual reason he had a timer and a remote)

You don't need to know why it explodes! You just need to know that it will!

Sounds like Mako’s predicament, right? Overloading the purple thing with lots of electricity so it goes away. Well, it should, because it is. Luckily, while neither Varrick nor Zhu Li (presumably) figured out how Spirit Vines work, Baatar Jr. sure as hell did.

Chicks dig giant robots automatons.

Now, one can argue that just because he had the most success, doesn’t mean he understood how they worked. But he did. He really did.



All right, let’s take this step by step. When testing the Spirit Cannon during “Operation: Beifong”, something extremely important happens that most of us, including myself at first, totally missed the significance of. Baatar actually manages to stop the Spirit Vines, which are already purple and active, from exploding.

That looks almost identical to the one that Varrick accidentally overloaded, right? Excluding the fact that this is a Foggy Swamp vine, they are. The end result, however, is not.

Where’d the energy go? Back to the spirit world. As we now know, Spirit Vines require a constant flow of electricity to conduct spirit energy. This cannon allows the vine to vent all of its energy in the form of a directed energy weapon instead of just exploding, thus circumventing that issue entirely.

Zhu Li damaged the ‘channeling ring’, which logically has something to do with how the spirit energy is safely transferred into the barrel of the cannon. If that is disrupted, the vine explodes just like it ‘typically’ does. Baatar Jr. was lucky enough to halt the vine’s reaction (probably because his machine is so much more complex than the feedback loop/ ‘basically just a battery and some wires’ setup that Varrick had. Lots of intermediaries between the ‘energy capsule’ and the barrel.) before anything bad happened.

As a side note, the ‘withering’ of the vine suggests that under typical conditions, Spirit Vines, once activated, lose a considerable amount of their potential conductivity when deactivated/over time.

Which then brings us to this moment:

Kuvira: What’s wrong?

Baatar Jr.: Probably something minor. I should be able to find the problem. The distributor pin is gone. I swear I locked it in place yesterday. There’s no way it could have just fallen out.

Kuvira: And this could cause the entire weapon to fail?

Baatar Jr.: It could cause it to explode.

That’s HUGE. Baatar Jr. knows exactly what he’s doing. Not only was he able to create a weapon specifically designed to exploit the ‘spirit vine energy problem’, but he’s displayed without a shadow of a doubt that he can distribute the energy to his, or rather Kuvira’s, needs.

Baatar Jr., for many practical intents and purposes, can energybend with science.

Okay, maybe that’s giving him too much credit, but you get the idea.

Regardless of how much credit he may or may not deserve, that, my friends, does finally brings us back to this:

The Mecha-Giant Spirit Energy Generator. The amount of power that thing is drawing from the Spirit World has to be astronomical if it wants to power not only the mecha-giant’s motor functions, but all of its internal equipment as well.

Because it’s immune to an electromagnetic pulse, since Baatar Jr. invented spirit-powered…everything? Radios, the cannon’s loading mechanism, the stuff that makes the generator actually function.

Not even gonna touch that. It’s not important in the context of this post.

What is important is that Baatar Jr. created a generator that can operate constantly without exploding. How? By redirecting the excess energy back into the Spirit World the same way it left.

The Spirit Vines.

(This also makes the generator sorta-kinda self sustaining, since it can’t be using electricity due to that EMP, and those Spirit Vines aren’t ‘withering’ from extended use.)

Yes, Baatar Jr. is actually taking a page out of Uncle Iroh’s book and redirecting pure energy to a more desirable target. Specifically, its origin point.

Now, that may seem like a random non sequitur, but let’s not forget how Mako was able to stop the reactor. It’s another thing that many of us, including myself, probably missed. And it’s why he’s even alive in the first place. Hell, it’s why he was even able to stop the reactor at all!

You see that? For this entire scene, Mako has been generating lightning at a constant rate, meaning that his internal ‘chi pathways’ are wide open. Not only that, but don’t you think it’s odd that he’s generating lightning from both hands? Sure, we’ve seen Ozai do that multiple times, but Mako isn’t hitting the vines with both hands. At first glance, it sort of looks like he’s just wasting energy, or that it may be just a stylistic choice.

But then I remembered this:

Mako isn’t wasting chi, and that generator is actively shoving energy into his body because he’s messing with the distribution system Baatar Jr. designed. The energy has to go somewhere. His arm just got burnt and his sleeve exploded! He’s actually redirecting the pure energy out of his off-hand and generating his own lightning simultaneously.

That’s insane! The generator is treating Mako like a freaking spirit vine, and it’s actually working.

Energy is flowing in and out of Mako at a level that would kill anybody who isn’t as ‘cool under fire’ as he is. In fact, I didn’t even know it was possible for energy to enter and leave the body like that in this context, but apparently it is!

As for how Mako knew that he’d have to do this before he even started, well he didn’t know for sure. But he did see something that gave him a pretty good hunch:

That is the direct result of Mako accidentally firebending the big clump of vines. And Fire is ‘energy’, so it’s not that odd for him to come to the conclusion that adding more energy to make it explode would probably have some violent feedback. Violent feedback that should have killed him.

But it didn’t, because it hit him right in the stomach, the big ‘sea of chi’, and he was already actively redirecting lightning. The energy flies out his off-hand (you can see some of his own lightning still flowing just as he collapses) and avoids his heart entirely. It still knocked him out, though. Probably because that’s really not how you’re supposed to redirect lightning. Same thing happened to Zuko during “Sozin’s Comet”, but he got hit in the chest.

So there you have it, folks! Thanks to all of this fancy-shmancy spirit vine ‘science’, we can now most likely conclude that Republic City didn’t explode because Mako was able to generate and redirect lighting long enough to force the Mecha-Giant Spirit Energy Generator to the point of overload which caused it to overcompensate and implode all of the vines.

Note: If you’re curious how this meta might play out in a post-canon narrative, I wrote a fic explicitly about it.