So, just so you know: this story is part of a series, but every fanfiction in the series is not linked with the others, as the only thing they share is the theme. They are based off different fandoms and they do not share the same universe. Thus, you don't need to read the previous story to understand this one.
With the arrival of Season 5, I feel the need to specify this: the story does not take place during a specific part of the chronology of the series, but it does take place before the new season.
WAR
2
"The Battle of a Man"
Target acquired. Preparing shooting program… Battery status: charged. Preparing aimbot… Warning: incoming enemy att-.. dos-.. er-… fzz..zz…
The robot fell to the ground in two different halves as Samurai Jack put his magic sword back into its sheath. The warrior took a long breath and relaxed his muscles. Around him lay the remnants of what looked like an entire army of black-coloured robots of various types. No one of them was still working.
Jack had just fought one of his hardest fights ever. His cloth was torn apart in various parts, and where it was there were fresh scars and lines of blood. The samurai was tired, but somewhat relieved.
He had been looking forward for this moment for a long time.
"My quest… is finally coming to an end…" Jack said to no one in particular. This time it was the Time, the moment where his struggles would have ended once for all. He knew for sure this wasn't a prank, a trick or something like that, and he also knew that in this one his greatest enemy couldn't try to stop him. At least, not with his common deceptions.
The only possible way was to directly confront Jack. And the samurai knew that, while Aku was a coward, he wasn't just going to let him get to the portal.
He was prepared for it: nothing would have stopped him now, not after he fought Aku and his minions throughout the Earth of the future for so long.
Jack marched towards the end of the enormous chamber he was currently in, avoiding the sharp shreds of metal and the remains of the robot army. In front of him a door of massive size blocked his path. When the warrior stopped, the door opened mechanically, like it had sensed the presence of a new visitor.
Jack waited for some seconds, glancing here and there, before resuming his pace. The new room he entered in looked more like a cavern rather than another chamber of the enormous stronghold he had previously sneaked in. This was the heart of the fort itself: it was quite large in size, though not as big as the previous room, but what instantly caught Jack's attention was the structure at the far bottom of it. A rectangular portal glowing of white, blinding light.
His goal. All Jack had to do was to reach the portal, return to the past and finish the work he had been forced to leave unfinished.
Jack began to run, as if he was fast he could somewhat avoid the traps left for him. But the samurai knew that it couldn't really end this way. That would have been too easy.
Suddenly, something black splashed away from a crevice on the ground in front of him. The warrior retreated and prepared his sword as the form began twirling until it took the form of Jack's nemesis.
Aku didn't seem to be preoccupied by the fact that Samurai Jack was dangerously near the time portal that could bring him home. In fact, the ancient demon showed a surprisingly bored face.
Jack decided to go for a direct approach. He leaped at him and with a war cry swung his sword forward. Aku modified his body and a hole appeared where Jack should have landed into. Thus, the samurai hit nothing but air and he landed, untouched, on the other side.
Jack immediately began running for the portal. If he managed to return to the past, defeating Aku in the future wouldn't have really mattered.
The samurai expected everything. Traps, other robots, the portal disappearing or being a fake copy of the real and hidden one. But nothing of this proved to be true, and while he got nearer and nearer, Jack felt for the first time in his entire life the feeling of an achievement. He was going to make it! He was going to end his quest once for all!
But something was off. Something deep inside Jack told him that this was just… wrong.
The noises of Jack's footwear faded and ultimately disappeared. The samurai was now only ten meters away from the portal. He could feel the energy radiating from it… he would have sworn he'd heard voices as well coming from the grey and black spirals.
But he couldn't move.
Slowly, Jack turned and faced the Shapeshifting Master of Darkness, who at the moment was casually leaning to a stalagmite, completely indifferent to him.
"What Samurai? Do you want to give me your last goodbye? Just go already!" the demon uttered when he noticed he was being stared at.
This had no sense. No sense at all.
"What trickery is this, Aku?," Jack bellowed, "I will not fall into your traps this time!"
The hint of an evil smile appeared on Aku's front face features. "Oh, I wasn't the one who stopped you samurai…"
The despicable demon wanted him to ask the first question. Jack knew it, and in normal circumstances he would have just ignored the event and tried to destroy Aku with his sword, but this time… it was different. He was a few inches away from the solution of all of his problems, and the ones of the entire world, and he needed to reach it. And to do that, he needed to find a way to unblock himself from his current state.
"Why are you not trying to stop me, Aku?" Jack said reluctantly. Aku finally abandoned his bored behaviour and approached the samurai. Jack's hand was already on the sword's hilt, but there was no attack directed towards him.
"Why would I do that? In fact, I have realized it doesn't really matter if you succeed or not in your quest, samurai. Because I will be victorious in either way!"
Jack blinked in surprise, "what's the meaning of this? As soon as I will return to the past, I shall finish what I left unfinished and your existence will end in both the present and the future!"
Instead of an annoyed expression, Jack was greeted by a demonic laugh. "You seem to be oblivious to the truth, samurai. Don't you realize that all of your efforts have been and will always be useless?"
"Enough of this lies, Aku!" Jack exclaimed, raising his sword, "I will pass this portal, and you won't stop me!"
"What samurai? Are you scared of the truth? Of the fact that I, Aku, the ruthless overlord of this pitiful world, didn't even have to move a single finger to take over?"
Jack froze before he could turn around and enter the portal. For some reason, his eyes fixed with Aku's, and the demon grinned in victory. He was in his hands now.
"When you left me in my first lair, long ago, I was weak and vulnerable, even with my great powers. Thus, I hid myself in the darkness, waiting for the right time to strike back and retrieve what had been mine. However, when I actually left the shadows and returned to the overworld, I was met by a quite interesting view."
Suddenly, Aku disappeared in an explosion of grey smoke, and Jack felt like something was trying to enter his own head. Aku wanted to penetrate into his mind, but Jack had been trained even in mind combat during his travels, and the demon did not find any opening at first. However, Jack soon realized that Aku wasn't really trying to attack him… he was offering him information, in form of images… Aku's memories of what he had not been able to see.
Letting the demon inside would have been extremely dangerous, but those memories were extremely important to stop Aku from taking over a second time in the aftermath, and Jack still had to understand why he couldn't make himself move and enter the portal. He had no choice.
He timidly reached out for a spiritual link and he was right away flooded with records of what once happened. Suddenly the samurai found himself in a wasteland… except for the fact that this one was fresh, and that battles were still going on. Villages and cities were on fire, and noises of battles of huge armies were heard. What was still standing showed a style that Jack recognized as the one of his own homeland.
This is the world when Aku had begun his ascend to the throne… It's terrible. I need to prevent this from happening!, Jack thought as he clenched his fists.
"Wait before jumping to conclusions, samurai," Aku's voice boomed around him. The demon was nowhere to be found, but his voice was definitely there, "this was not an effect of my influence. This is how I found the world when I awakened from my slumber."
What? Impossible!
"Don't you realize it, samurai?," Aku's voice chortled, he was definitely reading his thoughts now, "while I am the bringer of sorrow, I am not the only source of evil in this world. The humans themselves, in their arrogance and egoism, were destroying each other when you and I both disappeared. Their thirst of power brought them to fight wars that had the only effect to get them faster to their pathetic demise."
The image changed again, and now Aku was correctly visible on his throne while in front of him various men and women, leaders according to their clothes… were offering him gifts.
"But it didn't end there, samurai. Your race isn't totally stupid after all, and a genius wasn't needed to see the only entity that could save them from extinction. A superior power who could control them all and stop all the fights and wars. And that power they chose…" Aku waited some seconds, "…was me! I didn't even need to conquer the world myself, samurai! The inhabitants of it of gave me the power!"
…
This was… unbelievable.
Jack suddenly felt his legs weak. This was… no, it was not possible!
"Liar!"
The dream disappeared as fast as it had come into view, and suddenly Jack found himself back in the cave, the portal behind him, and Aku in front of him, boredom plastered on his face again.
"This is not possible! My father and his ancestors have governed the realm for many decades peacefully, and there is no record of wars different except for the battle against you, Aku. Even when I travelled throughout the countries of this world I all I found was peace which could only be corrupted by your own reign!"
"I expected you not to believe me, samurai," Aku said while watching in another direction, "but you don't seem to remember that I didn't tell you how it had been. I have shown you."
"Your deceits know no limit, Aku! I will not believe to your cursed tales or fake memories alike!" Jack responded.
Another smile appeared over Aku's face: "And this wasn't even the best part. That one is the fact that regardless of what happens to me, I will always prevail one day!"
The demon suddenly gained in height and size, like he prepared himself to say something important, "Isn't it obvious, samurai? You can defeat me, but one day I will return and take the position that has once been assigned to me!"
He approached Jack's face and he shouted, "I am the only cure for the illness of this world, and if your kind cares for itself, they will first exile you for destroying their only hope for survival, and then they will summon me once again!"
Finally, he moved back and crossed his black hands behind his tall silhouette, "This is why I don't care what you're going to do today, Samurai Jack. Because I now know that I will always win, thanks to the same people you've been helping until now."
Aku's words… he couldn't argue them. There was no way he could say he was wrong. If really men were that evil, if they were brought to fight each other naturally, all his efforts had been useless, and before it the ones of his father. Aku was still going to go back to his current position someday, or humanity will have disappeared from a ruined world.
He couldn't argue…
…but it couldn't finish like this!
"No!"
Aku raised a flaming eyebrow at the sudden cry from the warrior.
"I have travelled for years, Aku, trying to find a way back like this portal. But through all the evil that you have let loose on this world, I have always found sparks of hope. Men and women, creatures of all types, who tried to live under your reign keeping what made them different from you and your cursed servants! Miles away from the humans you're talking about!"
Jack stood up and raised his sword up over his own head, "this sword is not only the weapon that will doom you, Aku. It's the symbol of the good of this world, it has been forged to be so!"
Aku's bored face turned into a frown.
"You may be right in part, Aku, but mankind has never been perfect. There is a possibility to have a different cure, there must be one that doesn't consist in enslaving the entire world to your bidding. And I will dedicate my entire life to find it!"
With that, Jack turned himself to face the portal, now completely confident in himself, the block already removed from his body, "And the first act in my new quest will be crossing this portal and undo the future!"
But right before he could put the first foot into it, something caught him by his feet and flung him away from the portal. Jack was slammed hard against a rock wall, and chunks of the ceiling fell around him.
Aku scoffed as one of the tentacles of his octopus form moved back to his owner, "Umpf, I supposed you would build an entire false reality around yourself, samurai. To be honest, I don't care, as the knowledge that I will always win is an achievement even greater than your defeat."
Aku modified his shape again and morphed in the giant scorpion form, the claws ready to strike, "Do not think, however, that I will let you use this portal easily. As much as I'd love to see you fail miserably and go insane while the world burns around you, I don't like the image of my efforts in the last centuries disappear like dust. Show me what you have, samurai!"
The Japanese samurai assumed battle stance, his sword kept in his hands firmly. "I will!"
With a last combat cry Samurai Jack charged the scorpion form of Aku. The last thing he saw before falling into combat mode was the image of the world in flames Aku had showed him. Now it was not only a fight to save the world inhabitants from Aku. It was also a fight to save them from themselves.
END
Author's Note: For the few Samurai Jack fans out there, I deliberately didn't put much detail on the portal, how it works and it's able to get Jack to the past, and why Aku cannot directly deactivate, eliminate or take away this one. It wasn't, at least for me, important for what the story focused on.