The Green Ninja

 The identity of the green ninja ... A mystery that has been built up for the entire season up to this point. Now, it will finally be revealed! 

The episode opens with Kai dressing up in the green ninja's robes to try and get a clue to his identity, while the other ninja are training. Then, Wu returns alongside Garmadon, leading the ninja to form an uneasy truce with their former enemy. Kai, however, still harbors suspicions about Garmadon, and believes that fighting him will finally unlock his True Potential and make him into the green ninja.

This leads Kai to become obsessed with getting to fight Garmadon, completely missing the Serpentine moving to get the next Fangblade at the Temple of Fire. When the ninja finally get there, Kai's recklessness causes the volcano to be close to erupting, causing both ninja and Serpentine to flee, while Kai has to choose between getting the Fangblade and saving Lloyd. When he makes the decision to abandon his obsession with being the greatest ninja of all and instead save Lloyd, he unlcoks his True Potential, and also realizes that it is Lloyd who was always meant to be the green ninja.

 The Fangblade, in the meantime, lands near Pythor, who promptly makes sure to take it.

Various Observations:

-The episode's title would appear to foreshadow Kai being the green ninja, as he's obviously the one to reach his True Potential in this episode.

-It's kind of odd to see the green ninja's robes with the hood from the pilot episodes, particularly since this design only ever appears in this episode. I wonder why they didn't use a ZX hood yet.

-You know, I wonder if someone caught a glimpse of the scene with Kai wearing the suit, and then thought that Kai is the green ninja. 

 -As I've come to expect from Wu, his return has great comedic timing.

-Wait, where did Garmadon come from? He wasn't in the aerial shot, but then he's suddenly behind Wu?

-Oh, the falcon also helps the ninja look for the Serpentine and therefore the Fangblades. That's cool, I completely forgot it.

-Wu is completely in the dark about Zane and the falcon, and his reactions are great.

-"The Lord of Darkness just became our Roommate" ... sounds like a light novel, no? I'd check it out.

 -Apparently condensed evil is edible. And looks like worms. It even crawls around! I guess that means worms are the embodiment of evil. Now what does this mean for the Overlord ...

 -Garmadon laughs at a horror movie. A slasher movie, judging by the chainsaw. That's fair, I guess. Those films do have the potential to be cheesy enough to be funny, rather than scary. After all, you can't spell "slaughter" without "laughter".

-Also, this means violent horror movies canonically exist in a Lego property. Just wanted to point that out.

-Ah, Garmadon aqquired another power. He can apparently summon lightning bolts now, which seems rather odd, given that lightning is an established elemental power. 

-Garmadon's apparently not playing a video game right, because he's just shooting and destroying things. Oh dear, don't let Kai watch CallMeKevin, RTGame, LetsGameItOut, or any other Youtuber channel with similar content. Jim Pickens would break his mind. Garmadon would probably enjoy it, though.

-Kai's obsession with becoming the green ninja makes him miss the falcon reporting the Serpentine moving to the Temple of Fire. Perhaps the Fangblade wouldn't have fallen into the hands of the Serpentine if Kai paid attention. If so, you can also blame Kai for the Great Devourer being unleashed. 

-Wu seriously considers the possibility that Nya could be the green ninja. I'd probably think the same in his place, honestly. Nya got no particular training from him and doesn't even know about her elemental power, and yet she's still more effective than the main four ninja for the most part.

 -Kai makes a nice callback to Wu's words of wisdom from "Snakebit" when confronting Garmadon.

-With Nya declining to learn whether or not she's destined to be the green ninja, she's actually still left as an option, until the end of the episode where we learn that it's Lloyd who will be the green ninja. I'd like to see a a world where she really was the destined green ninja. Like the What If comics from Marvel. Well, I guess we saw her wearing the suit for a bit in season 5, but that wasn't her being the green ninja, that was just her dressing up to surprise Morro. 

-Cole is steering the Bounty. Usually it's Nya behind the wheel, no?

 -Garmadon gets his hand hurt by a single punch from Kai? Wow, maybe his constant stream of new powers is actually necessary to make him an actual threat.

-Alright, I call BS. Why can Cole immediately control his True Potential and only break down a door, rather than wrecking the whole ship, but Zane, who's constantly meditating, can't maintain the required amount of focus?

-Hm, when Wu talks about how maybe it would be better if Kai does not reach his True Potential, do you think he's thinking about Morro? Kai is getting similarly obsessive about being the green ninja.

-Why exactly is Nya staying back on the Bounty? Surely she could also help out! 

-Whoa, Wu is just knocking Serpentine into the lava! I kow Mezmo apparently just has his butt set on fire, but I'm pretty sure Wu is going for the kill!

-And here we have Jay using wind. He even calls it out like it's his element! This would be weird, even if wind wasn't later revealed to be a unique element, as this is the only time Jay ever uses any power but lightning.

-Neat, the Golden Weapons, in this case the Sword of Fire, once again cause devastation by being handled carelessly. In this case, the volcano erupts only because of the sword.

 

-Kai's obsession with proving his strength and becoming the green ninja leads him to use the Sword of Fire, making the situation far worse, leading the ninja to be forced to abandon the Fangblade. If you think about it, Kai is way more culpable for the Great Devourer's release than Lloyd.

-Wait a second, two versions of Bytar and one version of Chokun turn into two Chokuns and one Bytar! What's up with that? This seems like it should have been caught before the official release, no?

-Garmadon also throws Serpentine into the lava, but him trying to kill them feels perfectly in character.

-When Lloyd falls down, Cole immediately tries to reach for him with his scythe. Quick thinking there, I like it.

-The way Kai uses Spinjitzu to hop around with Lloyd reminds me a bit of Airjitzu. Many elements from season 5 here, huh?

-How, exactly, did Lloyd survive being in a fireball with Kai? Just because Kai unlocked his True Potential, doesn't mean that Lloyd is suddenly fireproof! Heck, even touching Kai should burn him, given that the ninja all turn into their element when they are using their True Potential.

-Gotta say, Kai's True Potential had probably the best build-up of the four. We had an entire season worth of foreshadowing about the green ninja, but the other three became less interested in proving themselves to be the greatest as the stakes rose, while Kai grew ever more obsessive, until he had to make a choice of whether to continue chasing his ambition, or save Lloyd, a former enemy that technically got them into the situation in the first place. By finally choosing to do what's right, not because it makes him a hero, but rather just because it is right, he is finally able to accept that he is not the green ninja, and reaches his True Potential.

 -All that praise aside, the way Pythor gets the Fangblade is really dumb. It just floats past him by pure random chance. Wow.