While the duo escaped, everything was a mess in the research lab of the White Sacrament after Shiro's explosive surprise.

This lab was far from human habitation, in the middle of a forest and hidden from sight so that the populace doesn't know of these vicious deeds as the White Sacrament had a good reputation to uphold.

They were human supremacist that totally believed in the human kind being the leaders of the world while every other species as evil but in most places in the Arc Continent they were a blessing to the people.

The White Sacrament was evil in the eyes of non humans but to majority of humans, they were the light of hope. The organization represented justice and holiness.

It had helped humankind from its humble beginnings to its current state where it ruled everything. It had disposed of cruel kings and nobles. It had given the poor people reprieve. It had introduced education and many other reforms to help the people.

Under them humanity grew at a faster rate as wars were stopped and most of the evil was shifted towards non humans.

With the White Lord's blessing, humanity had grown in physical prowess and magical prowess to rival the non-humans who were born with more advantages.

There were few among them that were corrupted and tortured the pure humans as well but they got taken care of once it came to light.

There were still corrupted nobles and such but it was underground instead of being open. The lives of humans were just improving and they were considering world domination under the order of their Lord.

The White sacrament considered monsters and even humans that had allied with non humans as lower beings and if a city or village harbored non-humans knowingly, they can end up getting massacred if they met one of the extremist.

These humans were also treated similar to monsters as they had betrayed humanity and the White Lord.

The White Lord was the master of light worshipped by the people of the Arc Continent. He was one of the immortals that resided in the upper dimension and interfered with humanity as his powers were enhanced by their belief.

He represented light and humanity. His usage of the White Sacrament had led to the destruction of places belonging to other Immortals on the continent, weakening them and allowing him to rain supreme.

Now those defeated immortals were his servants after he had broken into their domains and defeated them in mortal combat.

The belief and hatred towards the non-humans was a result of oppression during the era of the ancient demon king that had extended his claws towards the Arc Continent.

The Arc continent had been filled with monsters that tortured and destroyed human lives. The continent went through a dark age until heroes rose up among them to counter the corruption of humanity and the monsters.

One of the major forces was the White Sacrament. They knew that non humans also had similar characteristics as humans but they refused to acknowledge them as their Lord despised them. They didn't need to know and accepted it as it is, and used it for their advantage.

The Arc continent was massive, similar to the size of Africa with the Holy Empire taking up most of the territory while the rest was divided into Kingdoms under the authority of the descendants of the Heroes.

The lab was not far from the Port Town and was under the leadership of Bishop Judas. Judas was an old man in his fifties with a tall and sturdy structure with a long white beard and blues. He wore a special white priest clothing with golden lines that was made from mythril.

His appearance was like a gentle old man but he was the man behind the project called Heavens Soldier project. He was the chief of the White Sacrament Third Laboratory and he was preparing soldiers for the incoming war against the Non-humans.

He had been researching old magic and relics; from there he found the spells to summon individuals from other worlds.

He found that these individuals were empty with no magic so he devised a way to put dark magic into them so that they could fight poison with poison as monsters living in Pandora utilized dark magic.

Judas was a man of commitment with no fear and total loyalty to his Lord. He came from humble background, an orphan under the care of the White Sacrament.

He was a genius in his field and a powerful mage blessed by the White Lord.

Research was his passion and he spent most of his time with it, so he was away from his family most of the time.

In the outside world he was known as kind old man but inside the lab he was strict and decisive. His actions were inhumane and all he cared were results.

He was responsible for many atrocious acts in the name of research and he felt nothing of it.

With continuous cruel experiments, Judas had picked up bad habits as he had come to enjoy the screams of his victims.

Right now, Judas was intrigued and slightly angered at what had taken place. His laboratory was damaged, his subordinates were killed, research was lost and he had two subjects on the run.

It was a giant blunder in the spotless record especially since the new subject turned out to be a powerful mage, meaning the other world had magic of its own.

From Shirou's quick reactions and his fearless persona, Judas could see that he had summoned a warrior and not a scholar or a child. It was interesting and dangerous. Now they had to stop unless he wanted to bring someone worse than Shirou into the world.

Judas stood in his office and watched the video of Shirou's action that had been captured by the magical eyes of the Golems at the gate.

From his magic, Judas could tell he was someone that he could rival first class mages. Judas himself was a first class mage and the ones above him were the grand mages and the arch mages.

But that was just a conclusion made from second hand information. He was unsure of the qualities of the attack that was used as such the accurate power of Shirou could not be assumed, only estimates could be made for now.

Pacing around the room, Judas had his attention captured by Shirou. He wanted to know what the boy knew, the knowledge of magic and the secrets of the other world that the weak beings had no idea off.

Judas hadn't ignored the knowledge of the world and had recorded everything the outsiders knew. He was aware that the other world was technologically advanced beyond their time. The other world had weapons that could actually rival the top Apostles.

He had wanted to know more but the summoning was a magic beyond his understanding that was made by the Immortals so he couldn't control the process.

It only summoned youngsters and majority of them barely knew anything useful. But all of them had considered magic a fantasy, not real.

Regardless, humanity had gotten ideas about trains, communication, guns, cars, motorbikes, air ships, nuclear power, mech armors and magical weapons.

The other world didn't have many of the magical artifacts but humanity was very creative and they had imagined many useful things that Judas could work on.

The White Sacrament was already working on engines, air ships, guns and even armors that could increase the power of their army.

They had managed to power up their golems using the idea of energy compression for extra fuel and making a matrix that combined the energy capsules to increase their power.

It was still a prototype but the experiment had been a success and if they could capture Shirou than a new wave of advancement could be achieved.

Judas couldn't stop smiling at the thought of the wonders of the other world falling into his hands.

"Kotaro, track him down. Saito, follow him and provide assistance." Judas muttered in a calm tone as he looked at the two individuals sitting in his office.

Both of these young men were a product of the heavens soldier project, they were completed products and his weapons.

These two were the best among the group and they were total opposites as one was an assassin while the other was a frontline fighter that used twin swords.

Fuma Kotaro was a young man with a small muscular frame with red hair as he was mixed blood. He wore a ninja outfit according to his desire and followed the commands of Judas who had brainwashed them into loyal puppets.

He was a skilled fighter and master of traps, tracking and assassination. His weapons of choice were ninja wires, kunai, shuriken, poison pellets and small blade.

On the other hand, Saito was a tall man with black hair and black eyes. His body was slim but muscular and he had two katana behind his back.

He wore black leather armor that was easy to move in and had some parts that were metal for extra protection.

"Do we kill him, Master?" Kotaro asked in a dull tone like he was just a robot.

"No, capture him if possible but report back once you locate him." Judas didn't think they could defeat Shirou alone and planned to utilize the hunter squad or the Pegasus squad for this task.

He was using Kotaro because they had focused on the capabilities of tracking on this subject. He was the epitome of such skills and the ones above him were not available to him easily.

It would take time for him to get those services or he would have already asked the eighth Apostle who was a tracker.

"As you wish, Master." Kotaro bowed and left with Saito behind him. Shirou had left in a hurry because of the situation and left behind footsteps, as such Kotaro tracked using them.

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While the hunters were on their backs, Shirou and Kurono arrived near a village after getting through the forest.

Shirou had realized that he was leaving foot prints that could be traced with magic so he used magic to erase them after putting them in all three directions.

The footsteps now pointed towards all directions and disappeared after few steps. This should give them more time and a chance to get away from any trackers after them.

Shirou didn't have to tell Kurono to ignore the village as the teen was wary of any being of this world. So the duo bypassed the village and took a right turn while running at full speed to put up as much distance they could.

After some hours they arrived near some mountains and decided to find some shelter as they were both getting low on energy.

Shirou could use a magical pulse to map the area but decided not to as it would also give away his position, so they had to find shelter without any magic.

The mountain was filled with vegetation as such Shirou decided that they could take rest above the trees where no one could see them from below or above.

Kurono thought it was uncomfortable but what he had gone through was worse and he had slept on a hard ground, not a bed.

Comparing to that nightmare, this was fabulous so he agreed and the duo climbed the dense and tall trees for some rest while Shirou fried the birds they had caught along the way.

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A.N Hope you enjoyed and comment

Kuro no maou is an actual web novel and this is crossover with it. The story is about Kurono who is summoned and tortured becoming the demon king.

It is a dark story with heavy tragedy. The hero grows on the journey and he gathers team mates who also grow with him. It is a harem but its not instant and all the girls get properly established. The relationships are realistic and the love leads to battle between the girls as all of them are crazy and want to monopolize him. The mc isn't perverted and doesn't hold back from killing. He has dark magic and cursed weapons so he massacres when the situation arises.

It has some problems and isn't good as Rezero but I would recommend giving it a read. There is also a manga now, though it is less detailed and skips somethings.