Jack only uses a sword. A melee weapon. A weapon totally useless if the given opponent is outside his reach. So why doesn't anyone ever just try sniping him in the head while he sleeps or dropping bombs from an aircraft half a mile above his head? Aku not doing this is justifiable because he's Stupid Evil and generally a total moron, but why don't any of the innumerable bounty hunters seeking Jack's head try anything like that?
It's pretty well established that Jack always hears the projectiles coming.
One, what that guy said. Two, then the show would be over in a rather depressing way.
Why does Jack constantly not take a chance to return to the past in favor of defeating an evil threatening some people, when doing so would allow him to eradicate the source of all the evil? Bring up lawful stupid or Failure Is the Only Option and you'll regret it.
That aside, unless Time Travel in that universe can create Alternate Timelines, won't all the people Jack has saved throughout the series essentially vanish once he goes back in time and beats Aku? Assuming it will create a second parallel timeline (the alternative is way too morally dissonant), Jack has to beat Aku twice, once in the future and again in the past.
Actually, based on what similar plots have done, if he defeated Aku in the past, the people of the future would be the same except more prosperous because they were never under Aku's heel.
I always thought it had something to do with his own personal code of honour: he simply CAN'T ignore innocents in peril to go back in time because he places too much value in the life of innocents, and cannot simply sacrifice even one innocent person to achieve his ends, even through inaction. There's also the fact that he actually has TIME to save them: assuming Aku doesn't intervene, Jack can simply return to the past at the same point he left and finish the job, thus he can go back from any point in the future he likes, thus sticking around and sorting out the current crisis is no problem to him as long as he finds a way back in the end. Essentially, Jack's world DOESN'T run on San Dimas Time.
It still makes no sense; going back to the past completely would undo his actions in the future, unless his presence in the future would somehow create a duplicate version of him that would appear and fix the same problems in an Aku-less world. I honestly doubt that Genndy Tartakovsky planned that. Also, going back to the past and killing Aku would prevent THOUSANDS OF YEARS OF SUFFERING UNDER AKU'S REIGN from ever happening and would generally help the world on a much wider scale compared to, say, saving a group of generic Asian warriors - it's a much more benevolent action if you think about it. Jack's way of thinking seems illogical: "See, I could use this portal to prevent Aku from ever taking over the world, thus creating a brighter future. Or I could avoid doing that in favor of saving a small group of innocents. Yep, I'm sure that's the right thing to do."
You phrase it like he had much time to think about it. If memory serves, lots of problematic things were happening at the time when he saved said Asian warriors. He might not have been thinking straight.
It's psychological. Jack could just leave those people to their death, go back in time, kill Aku and rain happiness on the world, but it's just psychological that those people died when he could've protected them. Also, how does time travel solve paradoxes anyway? If it's alternate universes, then he really did just leave those people to die. Yes, he's saving trillions if he kills Aku, but he actually knew those people. Plus, he's a samurai, with honor and all that.
So knowing someone makes them more valuable? Jack has fallen prey to compassion he could go back into the past and akus world would never have happened, but compassion prevents him from doing what needs to be done.
I believe there's something you all may have overlooked - Jack has a feudal level of education. How in the world would he even be able to conceive of alternate timelines, or these people being utterly different thanks to Aku having never been there when he goes back in time? He had a struggle with the relatively simple though of being flung forward in time-so how would he be able to think of possible paradoxes or such from time travel.
Even if he knows about the possibility of alternate timelines, Jack wouldn't know if it were true anymore than we do. Yes, going back might prevent the Bad Future from happening, but there's just as much of a chance that it would cause a second one to form while the people in the first were still in danger. Without being certain that defeating Aku in the past would prevent the Bad Future, Jack won't risk leaving someone in danger if he has the opportunity to save them.
I think he's staying so he can get a few dozen extra levels so that when he goes to fight Aku in the past, it'll be even easier than the first time. I mean, look how easily he kicks Aku's ass when he runs into him in the future.
This is partially confirmed in one episode. Jack is about to go back to the past when the portal's guardian stops him with a vision of his  self and tells him that he needs to get to that point before he's ready to go back and defeat Aku. To put it in perspective, this◊ is what he looks like. "A few extra dozen levels" indeed.
Minor correction: Jack was out cold at this point, and the Guardian was talking to himself.
There's no guarantee that any of the method's he's found to return to the past would've actually worked. So, suppose he did ignore an innocent victim in order to exploit a device that failed. And later found out that traveling forwards in time is easy, but traveling backwards in time is impossible. Perhaps he can't afford to take that risk.
Also, it might be that if Jack left Future Aku around when he was next to the portal, Future Aku could also use the portal at the same time, travel back as well, and team up with Past Aku.
You're assuming that Aku is the source of all evil. He isn't, he's just the most powerful evil on the block. In addition to other points made about time travel not being guaranteed. The source of your potential time travel is evil? Well then look before you leap. The alien armies are attacking and you have a million to one chance that they will interrupt your time travel, which may not work, and innocents may die. Well not worth the chance is it?
Isn't it possible that he's afraid? Think about it, if Jack went back and killed Aku then this timeline wouldn't have existed for him to be sent to. So maybe he realizes that if he goes back he'll fail. Alternatively he just wants to deal with future Aku on the off chance an alternate timeline is created.
He may be aware of the chance that going back in time could create an alternate timeline. In that case, he'd basically be abandoning the world to Aku, with nobody to stand up to him.
Another possibility is that, even if Jack managed to, somehow grasp the concept behind time travel, he's still not 100% positive that he will defeat Aku, if memory doesn't fail me, he's been shown to still have doubts and uncertainties, so it's a possibility. He, however, is positive that he can make the difference for the people in distress now, so he chooses this option.
I made this same observation to a friend while we were watching this once, and his answer was the best one and probably the most accurate to Jack's characterization: that even though Jack knows, on an intellectual level, that he might keep those people from being hurt or suffering by using the time portal, on an emotional level he cannot get past the fact that he is leaving people to die when he is capable of doing something to stop it. Basically Jack cannot rationalize his humanity into being quiet and letting him do the logical thing.
When he was a child, he ran from his country and his father when Aku arrived. While it wasn't of his own volition, he must have felt that because he ran, his father and countrymen suffered for decades under the will of Aku. When he confronted Aku again, he hesitated and was flung into the future, dooming them again. Jack likely has a mental barrier preventing him from leaving people behind, especially if it's possible for him to do something about it. It's also understandable that he might also know that in the universe, there's a lot more ways back into the past. He only needs one portal to set him back to the time he needs to be. Also, as someone else mentioned, Jack may have indeed gone through portals already, just that they deposited him in random places in time, so he might risk losing one chance at going back in time because he knows it might not even be the right one, but he knows that those he sacrifices now will indeed die.
The above makes me wonder; Jack won't take a way back if there are innocents suffering, and innocents will suffer as long as Aku is around, so why doesn't he retry to assassinate Aku? Thinking about it, it bugs me that Jack hasn't realized that as long as Aku is around he can't in good conscience return to the past, not to mention that Aku has infrequently snatched or destroyed his means of doing so. So why wander around searching for time travel trinkets when his real mission (not a sidequest) ought to be to kill Aku.
Because Aku doesn't want to be found. He's capable of moving his castle, disguising it, hiding it from view, etc. The closest he ever got to assassinating Aku was that episode with the gangsters. He was this close to finishing Aku off when the gangsters sap'd him from behind. After that, Aku moved his castle; who knows where he went? TL;DR, It's a lot easier for Aku to find Jack then for Jack to find Aku.
Jack may be eons behind the times, but he's not stupid. He attacks targets of opportunity. He doesn't waste time trying to assassinate Aku because for the majority of the series he has no idea where Aku is. So he spends most of his time fleeing bounty hunters, performing random acts of heroism, and searching for ways to travel back to his own time. Notice though that in "Jack and the Gangsters", the very femtosecond Jack senses an opportunity to get close enough to assassinate Aku he immediately drops everything and seizes it (and comes damn close to succeeding, too).
Why is it that over the several thousand years that Aku had the Earth enslaved, those gods that made Jack's sword never thought to, I dunno, make another one? Or, God forbid, they get up off their butts and lay the smack-down on Aku themselves?
Well, they probably think Aku is a human-solvable problem. They were battling what amounted to a Cosmic Horror of infinite evil and darkness of which Aku is but a small hammy fragment. The Scostman's sword can probably kill Aku, and several of the magical doodads encountered on Jack's journey could harm him as well. Jack himself has already been a hair's breath away from killing him at least a dozen times as well, it's mostly act of plot that no one else (that we know of) has gotten close enough to try.
Or it could be that many people have gotten swords, as shown by the Irishman. It's just that those people always lose and/or Aku keeps flinging them through time. Once in the future, they try to make their way, kill themselves, or some thug/Aku finds and kills them. Perhaps Jack is just lucky to have survived Aku's fight, as well as emerging into the future. Or perhaps there are hundreds more like him, phasing in time, living out their lives as rebels, and eventually dying. Aku's reign has apparently lasted thousands of years, so that's a lot of lifetimes.
The Scotsman. Aside from that, those Gods have the entire universe to look after. In the big scheme of things, Aku might not be a real threat.
Considering the many, many threat's Aku's thrown at Jack, it's not a big assumption to say that a lesser warrior wouldn't have a prayer of lasting long enough to get near the Big A, let alone defeat him.
If the portrayal of Ra in "Jack in Egypt" is any indication, the gods in the Jack-verse are clearly the mysterious kind. Whatever plan(s) they may or may not have, they're not sharing it/them with us mere mortals.
Jack trained all over the world for years before returning to face Aku, most of the people he learned from are dead. Another thing is that the Gods helped defeat Aku the first time because it was their fault for not checking. They left it up to Jack's Dad to defeat Aku because he'd given him a physical form. They helped stop Aku the first time because it was their fault he existed in the first place. But the second time, he'd been set free in a completely different way that the Gods aren't responsible for. So the simple fact is, as mentioned before, they've got a huge job of watching over the universe, they helped took care of Aku once because they were responsible and after that, it was no longer personal enough for them to get involved.
When Jack is about to slay Aku, why is it that he (Aku) has the energy to hurl him thousands of years into the future, but not vaporize him?
He's stupid? He shows this many times in the future.
We don't know how Aku's magic works. Maybe flinging open random portals takes up less "mana" than his eye beams do. Maybe he was desperate and just used the first spell that came to mind. Or maybe he thought forcing Jack to live in a world that was neatly wrapped around his finger would be more satisfying than just killing him.
Aku had attempted and failed to kill Jack several times through out the fight. Jack was essentially bypassing all the attempts on his life with minimal effort, thus Aku was able to discern that killing him at the current time was impossible. So he did something Jack would not expect. Considering the course of the fight already, if Aku had attempted to simply kill Jack then Jack most likely would of evaded or stopped the attack and finished him off.
Also, the 'fling him in the future' trick worked up pretty well: as soon as he arrives, Jack is hit by three different flying cars and nearly gunned down by a fourth before he can even start to understand where he is and what's happening precisely because he has no idea where he is and what's happening. Then Jack starts understanding where he is and what's happening... And nearly had an Heroic BSOD when he learns that Aku rules and, as far as the three guys he's speaking with, it's always been that way. A lesser man would have been killed by the cars or broke down upon learning how bad he failed...
What if that "flung" actually was his "exit-strategy"? Just imagine some Gollum-ish Scene with Aku trying to deal with the sword he knew could hurt him, and which he was unable to find after defeating the man who originally wielded it:
Aku(worrired Voice): What shall we do if someone ever finds the sword and steps forth to oppose us?
Aku(mischievous voice): Then weŽll just kill him!
Aku(confident voice): YEEEES! WEŽLL JUST KILL HIM!
Aku(worried Voice): But if we canŽt?
Aku(another worried voice): Yes, what if we canŽt?
Aku(bored voice): Argh, canŽt we just deal with this later?
(Realises what he just said)
Aku(mischievous voice): Yeeeeessss...weŽll just deal with it later ... muahahahahahahaHAHAHAHARHARHAR!!!!
In this (fake) context, the time travel would be a back-up plan Aku prepared BEFORE the battle, just in case it would come to the exact situation that forced him to send Jack away. Of course he could have made that prepared spell a lethal one as well, but assuming he wouldnŽt be able to kill him before, a different approach(trying not to loose instead of winning) would make this a very logical choice.
Just what is Jack's name?
It's deliberately never stated. In the first episode he takes up the nickname Jack, however he never states his real name, and quite possibly for good reason: considering how much time travel tech Aku has stolen/destroyed, it's possible Aku now has his own methods of going back in time. Therefore, knowing Jack's real name would mean Aku could just go back in time and kill Jack when he was a child, thus preventing him from ever rising up against him, and ensuring that he rules for all time.
But Aku already knows Jack's father is the Emperor - if he really needed to know Jack's real name all he'd have to do is ask.
It seems to be more honor related than anything else: Jack had spent his entire life preparing to kill Aku and take his homeland back, but just couldn't finish the job when it counted. He failed so badly that the entire galaxy suffered under Aku's reign for thousands of years. He doesn't reveal anything about his name or homeland because he feels that he's not worthy of taking his birthright until Aku is dead.
The only clue this Troper found was in the episode, "Jack Under the Sea", when Jack is about to introduce himself to the Triceraquins. He says that his name is, "G-...Jack.". It starts with a G.
Whatever happened to those guys whose essence was stolen by that major Aku minion, Demongo? We see him getting creamed by the numerous essences of the guys he stole over the years, I kinda wished they'd bring them back at some point...
Well, considering that Aku finished off Demongo, those guys probably moved on to the afterlife.
This troper was interested to note that one of the creatures assaulting Jack in the graveyard bore a strong resemblance to Demongo, who was quickly dealt with by Jack.
Why is it that this is a dystopian future where the planet has been stripped of all resources...and yet the most common scenery on the show is huge stretches of pristine wilderness?
Because Humanity and its various offshoots, uplifts and variants are mostly gathered into centralized areas where they can be tightly controlled. As long as the remaining areas are too low-tech to threaten Aku, he doesn't care what refugees huddle out in the wilderness. Consequently those areas are relatively unpopulated and have returned to their natural state over the thousand years or so since Aku conquered the world. (Not that that situation makes good strategic sense, but as stated above Aku gets by on pure brute force, not brains.) The "resources" stripped away are probably mostly metals and fuel, and trees can grow without iron and coal deposits under them.
True, but consider that the episode began with Jack failing to capture the same time portal doo-hickey and being left humbled and humiliated on the ground as Aku flies off with it. If the episode ended the same way, with Jack suffering a similar humiliating failure despite spending the entire episode learning to jump good, that would be quite the Downer Ending. The real problem with this episode is that it's rather pointless from a narrative perspective. Jack learns how to "jump good" in order to help him capture the time portal, and then...fails to capture the time portal, making the whole "jump good" training montage a pointless exercise. The monkeys learn how to fight and defend themselves from the gorillas, but they're never seen or mentioned again so seeing them learn to defend themselves was also entirely pointless. This episode would have worked better if it had aired right before the episode "Jack and the Monks" where Jack becomes crippled with depression after suffering multiple crushing failures and has to be reminded what he's fighting for.
I think the issue is that the episode ends with Jack catching Aku completely off-guard, in such a way that it looks like he's on his way to finally succeeding in his quest... and we never hear anything about it after that; the next episode is back to status quo, with the implicit assumption that no, he failed again.
It's entirely possible that the time portal jumped Jack back in time, say, five hundred or a thousand years...or had some sort of catch preventing him from using it to get all the way back to his own time, similar to the (evil) magic well in an early episode.
It's also entirely possible that he beat Aku, who retreated, then the portal turned out to not be something that suited his needs. For example, it might have been a portal in space rather than time, which is certainly useful, but it won't send him back in time. Also, most time portals appear to have some sort of thing about them making them not a 'quick fix', the guardian of one portal and the evil nature of another. So beating Aku may have not been what it took to use it, maybe he needs to find a spell of some sort or something to use it. That and the ability to Jump Good was actually used quite a bit after that, so Jack did get use of it.
Up until this point, Aku's been trolling Jack- you can see it here. Then, after Jack learns how to Jump Good, we never see Aku screw around with Jack that blatantly ever again. Jack may not go back to the past that episode, but he did kick Aku's ass so hard that Aku remembers why he was afraid of Jack in the first place.
Sicne Aku was holding the portal, it would have been easy for him to throw it in panic. Either far away or throwing it down so it smashes and breaks.
I was just watching Jack and the Zombies, and something bugs me. Aku's watching Jack through his magic mirror, sees Jack throw a stick to determine what direction he'll go in, and Aku telekinetically moves the stick. Okay...if he could that through the portal, why doesn't he do the same thing with his omega beams and just fry Jack while he's asleep? Or just send a never ending stream of minions through the mirror, directly to Jack's location?
The first one likely wouldn't work. The second is what he does all the time. Jack just keeps killing them.
Maybe because it's not a reach-out-and-touch-someone kind of portal? If it was, Aku would probably have no problem doing just that...except that he likes to play with his food, so to speak. Anyway, telekinesis only requires that you be able to focus on the object you're trying to move. In other words, you only need to be able to see it; kinda the point of telekinesis, don't you think?
I dont think it was even telekinesis, it seems like Aku can slightly alter probability at a distance.
In the episode with the warrior trapped inside the rock golem... Why didn't the warrior try to leave the mountain, attack Aku's troops, and die in battle that way? He gets to go to Valhalla, and get some small revenge on the demon who trapped him in a And I Must Scream position. Nothing ever shows that he is tied to the mountain or anything...
Doesn't make for a very good episode though. I guess the golem was there long enough that if he could leave he would. Since by that point in time he hadn't we can reasonably assume, for whatever reason, he couldn't. I'm sure there is a great explanation for why this is but explaining all that wasn't important to the story, would you prefer an entire episode just explaining in detail the minute specifics of a curse cast on some poor one episode character?
More to the point, Aku is a sorcerer. An immensely powerful one. He wouldn't have fought - he'd have just smashed the warrior into atoms and sent him back into the rockbed and made sure he stayed that way.
I don't think he knows Aku is still alive and is currently in control of the world.
The Warrior isn't capable of leaving. He's trapped in the mountain by Aku's spell, which prevents him from leaving. Sure, he eventually gained the ability to (magicially? telekinetically? I'm not sure) move the rock around him to create a body and death course, but it's limited to a certain distance. If he eventually became capable of leaving he no doubt would have, either to hunt down Aku or find a warrior that could kill him, it would have been a lot easier and quicker than what he did do.
Why exactly didn't Jack and/or the Scotsman just cut off the handcuffs in episode XI, instead of waiting for the humongous bullet?
Cutting a chain in half is not easy. Not even (I would imagine) if you're using super-duper magical swords to do it.
...harder than cutting through armored, solid metal robots on an hourly basis with no apparent difficulty? The sword's cutting ability has only ever once been questioned, that I can think of, and that was against revolutionarily advanced war robots.
Yes, harder than cutting through armored, solid metal robots (potentially). Chains don't sit still when you hit them, and that blunts the impact. Also, it would have been an awkward angle to cut from. Also also, we have no idea what kind of super-awesome un-cuttable metal alloy those chains might have been made of.
Another thing, both of them wield two-handed weapons. The power of a stroke from a double-hander is from changed angle of your hands as well as the swing of your arm. The two of them being chained would have little arm swing and no hand angle, reducing or eliminating their cutting power.
Maybe they couldn't agree on who should be the one to cut the chain because neither one of them trusted the other not to, say, chop the other guy's hand off.
Rule of Cool: Jumping up and letting a huge bullet shatter the chain is way cooler than just cutting it.
What was it that freed Aku from being sealed by Jack's father? At first I thought the seal weakened on its own after a few centuries, but Jack was shown to have been born just prior to Aku being defeated the first time. Aku is then shown coming back when Jack looks to be about four or five years of age. A really short amount of time for the swords effects wearing off enough for Aku to break free. I also don't recall it ever being mentioned someone intentionally freeing Aku. On a related note why didn't the Emperor just kill Aku in the first place instead of making him Sealed Evil in a Can? The sword seems to have the ability to destroy him permanently.
I always assumed it was part of some elaborate Gambit Roulette on Aku's part. Maybe he tricked jacks father into thinking he was dead by sealed himself into the tree until a set of astrological circumstances were met. That way he can use the time in the tree to recharge his mojo, same as he did to jack, and then catch Jackdad off guard. O.K. not that brilliant, I just like to think that aku and jack are 12th level intellects and that the shows non-sequiturs are part of the elaborate chess game they play with one-another. Jack never get's back in time because Aku has put multiple levels of blockage in place that make most methods of time travel ineffective. Aku can't be assassinated because Aku's lair cannot both exists in a sub dimension and has it's entrances shuffled around the universe randomly, and aku never leaves said lair without everything planned out. Wow, I'm way off topic.
About the Emperor not killing Aku, he explained it in the very first episode: he thought that the sword would do all the job, and all he managed to do was to seal Aku away. When Jack expressed a similar view, he immediately corrected him, warning him that it was only a tool and that his mind would set the path to slay Aku in spite of his deception. Long story short, the Emperor tried and fucked up, but realized where he failed and told Jack how to do the job.
The first episode opened with an eclipse and the Aku-tree reacting to it in some way that undid the seal, setting him free.
In "Jack vs. the Lava Monster." I was totally waiting for the Viking to, as the Valkyries took him to Valhalla, say to Jack something along the lines of "I will save a place for you in the mead-hall, my friend. I eagerly await your coming." But it didn't happen!
He knew Jack wouldn't die in battle, as we seen Jack will surely die from old age after ruling the his kingdom after beating Aku, that still surely wont prevent him to give him a visit tho, with enough titles as he already has.
Jack isnt a viking for one, and doesnt follow the Norse faith. Most likely there are three afterlives since there are three gods shown in the series, its likely that Jack's people worship the Vishnu standin.
During the quest to get the time travelling jewel, Jack falls into a pile of quicksand. Why didn't Aku just let him sink? Aku explicitly tells Jack that he destroyed the stone to prevent Jack from going back through time. Well, he would have a hard time travelling back to the past if he is drowned by sand.
Perhaps he has some degree of respect for Jack? Letting him die in quicksand probably would've been an 'unworthy' death for his ultimate opponent. There's also the possibility that Aku simply believed Jack could've got himself out of there. If he hadn't helped him, then Jack might've realized the trick, escaped, and now known Aku was tricking him, ruining the plan.
Think about it this way: By this time in the series, Jack has spent, let's say, a couple months in the world run by Aku. That means his fight against the dark lord could inspire others to tamper with time and wipe Aku's reign away. Remember, Jack was the only one who knew the location of the gem, and the test required to use it. As long as that crystal remained, so did the threat of Aku's destruction. Additionally, it could be that Aku doesn't want him dead yet; he wants him broken spiritually beforehand. Killing Jack in battle (letting him die while on a quest to stop him) would make him Martyr Samurai Jack. Convincing the warrior that his is a fruitless effort would be a grander victory (and almost happened in a later episode).
Kill him? Without seeing the expression on Jack's face when he realizes he's been tricked and used? I think not!
At that moment, before Ikra pulled him out, the look on Jack's face was one of rejection, not impending death. He was sad that Ikra seemingly abandoned him (she didn't miss a beat while running off into the distance). He probably had a way out of it, and Aku knew. This is the same guy who survived being hit by a car and blown up on a regular basis.
Okay, so why doesn't Aku, upon the very first time he has difficulty with Jack after having thrown him into the future, throw him further into the future? Any time Jack gains allies, Aku could throw him into a future in which those allies have aged to death. Any time Jack learns a skill, Aku could throw him into a future wherein that skill has effectively become obsolete due to the latest technology. Any time Jack's questing after a MacGuffin that'll get him back to the past, Aku could throw him into a future in which Aku's already found it and dealt with it. No, it probably wouldn't make good storytelling, but it'd make a modicum of sense; just saying, it'd be nice if they could at least provide some explanation as to why this doesn't happen, other than just assuming Aku's an idiot.
Maybe Aku can only use that spell once, or once per person. Of course, that's a pretty weak answer, so I submit the following as well. The first time Aku used that spell, he was on his last legs, and caught Jack completely off guard. Also, Aku seems to need to be there in person to cast that spell, let's just say that he does confront Jack again, and he tries doing what you say, Jack might be expecting it this time, and he would be able to react to it better than the first time.
Without knowing the default rules for time travel in the SJ universe - and without knowing the rules of Aku's particular style of black magic - how can we know the limitations of either? The fact that he doesn't is the only evidence that he can't. No, the real nasty move would have been to get Jack's sword from him - it was managed a few times - and then hurl the sword into the past.
The time portal was a last ditch effort by a beaten foe on an opponent far stronger than him, Aku CAN do it again, but he'd have to get close t oJack to do that, and Jack wont fall for the same trick twice.
Was "Seasons of Death" a WTF? episode, or was that just me? Yes, some of it was very coolio, but what was with the whole spring part? Did anyone get that?
It might have been a Secret Test of Character, to see if anything can distract Jack from his quest. It might have been an intentional parallel to the "Summer" segment that began the episode - unlike that segment, the antagonist isn't a mirage and could very well entrap some other unlucky traveler in the future. It might even have been intended as something of a Subversion of the typical Jack formula; the nature sprite is one of the few antagonists that Jack never defeats/kills; he brushes the whole thing off as a hallucination.
Its just a visually interesting story, it doesnt have any deeper meaning.
In the opening narration, Aku mentions that he unleashed an "unspeakable evil". It sounds like he's talking abotu an Eldritch Abomination, but the image is pretty much Aku. So he unleashed himself from a prison?
The "unspeakable evil" refers to his actions. Not an entity.
Was it supposed to be obvious that Ikra was really Aku because I'm not really sure honestly.
First time watching it I had no idea. The second time however, it is pretty obvious. Ikra shares the same colors as Aku (black, green, and red), the person Jack talks to at the start warns of great evil just as Ikra arrives, and the shape-shifting toward the end was a good giveaway (even first time viewers started to catch on by then). However this episode set up Aku's transformations and made them easier to spot down the line, making it more obvious now.
Is Jack's sword harmless against an innocent, or is it useless in the hands of evil? I've seen it described as both on TV Tropes and I'm trying to figure out which is correct (yes, they're not mutually exclusive, but I doubt it's both).
If I had to guess, I'd go with "harmless against an innocent." While not the best reference, in The Aku Infection Jack (being possessed by Aku's evil) slashes at several of the salamander monks, but none die. However because Aku's evil is possessing Jack, if the sword was useless in the hands of evil, it wouldn't do any harm at all. To add to this, earlier in that same episode Aku-Jack killed an innocent robot, so the sword is able to harm at least some things when used by evil. It just can't kill innocent people I guess; the real question is "what is considered innocent?"
I remember the quote as "In the hands of evil, it can never harm an innocent." Meaning only a good person could harm an innocent with it, but an evil person can harm non-innocents.
As I recall there was one episode where Jack tries to kill a deer for food, and it turns out the sword can't cut it. So it's probably just that it can't harm the innocent no matter what the morality of the one who wields it is. Also, I think killing an innocent robot is allowed because the sword doesn't recognize it as a living being.