The White-haired Demon

When Kai reached 50, the Armies developed a new potion that could enhance a soldier's lifespan above Captain level.

Where did this potion come from, who brewed it, and what were its ingredients? No one knew. It did do the trick, though. All Captains, Commanders, Generals, and even Supreme Generals began taking this potion, enhancing their lifespan by a few years.

And the potion's quality kept becoming better as time passed by.

From then on, Kai began taking extra care of not leaving his blood stains behind. Late he might be, but he had indeed guessed a few reasons for these advancements.

When Kai became 80 years old, he had already spent 62 years on Island X.

His true age, however, was only 25.

Selene did bring new colors to his monotonous life, and so did Murasame. The two killing machines, under the command of Blood Demon, ravaged the populous of Island X, killing hundreds of Troopers in one go.

No matter who it was, what it was, and where it happened, those who got nicked by One-Cut-Killer, all died.

Then there was Selene, the soul assassin.

By the time someone realized that a foreign lifeform had invaded their bodies, they would already be dead.

Yet, even more fatal and shocking, was Kai himself.

He had only gone to the Samurai's Hut a few times, learning from Samurai Jack the art of micro-movements. But those few times had been enough for him to realize how wrong he was.

How wrong he was, for him to become so dependent on his Instincts, on this Observation Haki. This wasn't the right way. Not for him.

With this realization came more pressure, making Kai fall into more rounds of hellish training.

Every day, Kai spent hours training his physique, becoming leaner, stronger, and faster. Selfless Breathing followed physique training, occupying even more amount of time.

Kai had always known that he might never reach the Constant Breathing from the Demon Slayer World, where a Demon Slayer could maintain his Breathing Technique for 24 hours, even in one's sleep. He had also known that he might never create another transformation, for his transformations like Three-headed Vritra relied on Comprehension and sudden Epiphanies, not on training.

It didn't come as a surprise that the progress of every second and every minute in Selfless Breathing was becoming so difficult that even after so many years, Kai could only use Blood Flames for 90 minutes.

The rest of the time that left after both mental and physical training, which was already minuscule, went into hunting, killing, and eating.

In essence… Surviving.

After unlocking Selene, in the past, Kai had returned with a plan in his mind, putting his failure to the back of his mind.

Sounga needed 2 million Points to unlock, and the Book needed 5 million. The Items and Powers he couldn't use, Kai had never given them any thought to unlock, like Eon Soul Dew and the Title, Death Scion.

Kai had wanted to unlock Sounga as fast as he could. So he had begun killing madly.

His killing sprees had gone so out of control that the Armies, those who had shut themselves inside headquarters, came out in huge numbers.

The smell of blood that day had reached from coast to coast, the name of White-haired Demon resounding throughout Island X.

Yet even that massacre failed to give Kai all the points needed.

Kai had also given himself an ultimatum to not spend over 12 years between any 2 visits to the Samurai's Hut, as the Life Halt Capsule only halted his aging by 10 years.

So, he had gone back to Samurai Jack, unlocking many Titles and other Items instead, hoping to return to the Samurai's Hut with ample Points if he were to fail Jack's task this time as well.

Alas! The next time was the same, and the next to next as well.

No matter how many soldiers Kai, Selene, and Murasame killed within a decade, the number just didn't surpass 2 million Points.

At last, when Kai became 110 years old, he and Selene devised a brutal plan.

They would infiltrate Death Eater's HQ and kill as many as they could before the General stationed there sensed their presence. Kai wasn't worried about Commanders, as few soldiers of their powers could catch him even if he wasn't their match.

Moreover, Eternal Snow headquarters all had several Companies of Wights, the undead, making it impossible for Kai to plunge deep into that pit. Not without having dozens of daggers made of dragonglass, at least.

Pokemon Troopers of the Original Ones Army wouldn't be able to resist him, either. But, in their case, killing tens of thousands was almost impossible before getting discovered. There were just too many types of Pokemon for him to remain unnoticed.

The Star Beast Brotherhood Army had Yautja and Xenomorphs. Kai was sure of killing any of them. But when hundreds of Xenomorphs worked together with even more invisible, armored Yautjas, even Kai's Instincts were bound to fail in those cases. He rather not go there, when he had better alternatives available.

Wizards and Witches, if Kai were to ignore magical creatures, all depended on wands, casting and chanting spells. It wasn't like Darcie, who just had to glare hard to bring out stupendous Mana. Almost all spellcasting involved chants and wand movement, which were crucial to magic. It was especially so with Trooper and Captain level soldiers.

One could even say that with Kai's Observation Haki, they were his natural prey.

So, Kai began preparations to infiltrate Death Eaters 3rd HQ.

It was the only headquarter which had no other headquarter in a circle of 250 km radius around it, making it quite lonely. That it belonged to Death Eaters was pretty coincident which Kai didn't mind.

But only another decade later did Kai's all preparations end.

The time between 110 and 120 years of age, Kai spent mostly in training, only occasionally going out so that the Armies wouldn't sense anything wrong. He didn't even hunt as crazily as before.

Just a month before, when he had planned to visit the Samurai's Hut, Kai infiltrated the 3rd HQ of Death Eaters on a cold, rainy night.

Over half a century of training in the wilderness, surviving the onslaught of ever-strong abominations, and killing had turned Kai into a ghost even he had never imagined himself becoming.

Rain pattered hard, roaring around the gigantic castle and the mountain. Hundreds of Dementors were patrolling around the headquarters, their breath rattling.

Dementor-Kai, and his two Dementors, melted among them like wraiths.

Troopers' barracks were outside the castle, so Kai didn't even need to go in there. Selene became a cloud of wet mist in this downpour, all magical spells failing to keep her Intangible form out of the ground.

No one screamed that night. No one gasped.

There were no warnings, either.

On one side, Selene kept bursting out with 100% Soul Chill, killing thousands of Troopers in their sleep. On the other side, Dementor-Kai kept slitting throats, poison-coated Murasame killing at the slightest nick.

By the time the first shout awakened the entire castle, Kai and Selene had already scoured an entire slope of the mountain, housing over 16000 Troopers.

"Enemy!!!!"

"Ahhhh!"

"Hahahaha!" Hisssss!!!

With the cover gone, roaring blood flames hissed out of Kai's mouth, covering his entire right arm from the tips of his fingers to his shoulder. Selene rushed in and out of the Troopers, killing as many as she could before the time ran out.

Crack! Crack! Crack!!!

Three soldiers apparated at the sight, their eyes falling on the streams of blood melting into the rain.

Kai stopped and looked up toward the three of them, Murasame reeking of death in his left hand. Despite being wet, his long, white hair fluttered in the merciless, stormy winds. His long and lean figure was chiseled, his face as handsome as a devil. His upper chest was bare, and he was wearing baggy army trousers.

At 6 ft and 2 inches, Kai indeed looked like the fabled White-haired Demon who was famous among the Island's soldiers; who they all hated and feared.

"You sure have guts!" a feminine voice rang through the entire mountain, making all survivors look toward the origin with fawning gazes. "Coming to my turf, killing my soldiers, and then even smiling at me. Humph! You think you can leave alive?"

If it was anyone else saying these words to Kai, he would have already vanished, beheading them. But he knew… this woman was worthy enough to make him feel uneasy.

Her hair shone darkly on this darker night, but even that couldn't hide her green eyes. As she stood there, her tall figure looked no less impressive than Kai's own. Mana rippled around her, making all raindrops flutter like a sheet of smooth fabric.

When she looked at Kai, anger and disgust came pouring out from the depths of her soul.

She wasn't alone, though.

On the woman's left, there was a bearded wizard, wearing round glasses. His height was short, but his back was as straight as the woman's, and so were his eyes, greener than anything. The pelting rain had made his hair stuck to his forehead.

But even then, Kai caught a glimpse of a mark there. A bloody mark… like that of a lightning bolt.

On the woman's right, there was another bearded wizard, the tallest of the three, with dark eyes. From top to bottom, he was clad in black, his long, black hair spilling over his shoulders.

This woman… This witch… was one of the 6 Generals in the Death Eaters Army, and the two men were her most powerful Commanders.

General Lily Potter, Commander Harry Potter, and Commander Sirius Black!!!

Kai looked at the three of them, felt their power and their rage, and smiled. They still hadn't discovered Selene, thinking that he alone had killed so many of them. He must buy the Ghost Basilisk more time. Otherwise, he must return to the Samurai's Hut once again with insufficient Points.

No. He had had enough. He would try…

Kai wanted to try… killing a Commander. A true Commander.

"You know," Kai said, grinning, looking at Lily Potter. "You need a dick in your life."