A/N: Hey readers! i am up with a new crossover fic from a request from my old friend tython055.

I hope you all like the idea he has come up with!


Prologue

Baghdad, Iraq, January 26, 1258

Within the very wall of Baghdad, tension was at an all-time high. Why? Because the Mongols were practically close to their borders.

It all started when the Mongols invaded neighboring settlers outside Baghdad's wall. They learned of this when the survivors begged for shelter and warned them of the coming invasion.

Thus, countless guards were preparing themselves for the coming fight, numerous refugees were staying in tents in the streets, and many poor and injured people were being tended to.

"Unbelievable… to think there would be these many refugees." One guard watching the scene said to another who accompanied him.

"Mongol animals…!" The other guard growled in distaste seeing the state of the people.

"Move aside! I have another injured on the way." The two guards immediately moved out of the way when they heard the yelling behind them.

They see two other guards holding a stretcher that an injured-looking adult woman covered in bloodied bandages on some parts of her body was resting on and what is odd was she had a long object garbed in cloth protectively in her arm. The guards watched the injured woman being sent to one of the available empty tents.

"Curse those Mongols! Have they no shame?" The guard watching the poor woman sent to the tent growled in rage.

"Indeed… but what was that thing she was holding?" The other asked, both angry and curious about what the injured woman was holding.

"Does it matter? What matters is that woman is now safe." The guards said as he walked away.

"I suppose…" The other guard trailed off as he followed him.

The two guards gently placed the woman on the ground in the tent.

"Gods above… the poor woman." The guard said, sad as she looked down at the sleeping injured woman.

"I can only imagine what she had to go through…" The other guard agreed with him but also looked down at the item the woman was holding. "Should we do something about the item she is holding?"

The other guard shook his head. "It's clear that it holds some meaning to her. It's only right for her to hold it."

"I suppose…" The guard agreed. After their discussion, the two left the tent to aid the others, knowing that the injured girl should be best left alone and sleep with injuries like that. She can't go anywhere.

That is what they all thought.

"Malaka… I thought they'd never leave…" A small groan came from the woman as she opened her eyes, and the long-garbed item she was holding began to glow, and suddenly all her injuries began to heal as if they were never there.

The said woman slowly stood up and slowly stretched as she took off the wrappings that once covered her injuries. Then she stood up straight with confidence and strength renewed.

This is Kassandra, the old Spartan mercenary of Greece of old.

"The Staff of Hermes really is a god sent." Kassandra chuckled as she ungarbed the said staff showing its glory. Looking at the staff, Kassandra could only think of how much history the ancient relic held that granted her immortality; thus, her injuries were healed.

"Now… to gather some armor." The former Spartan mercenary said as she looked around the tent. Convenient since some armor and weapons were available in the tent to arm herself.

As she slowly armed herself, she recalled the reason why she took drastic measures to infiltrate Baghdad.

It was a year ago during her travel to Masyaf after being raided by the Mongols. Settlers near the area claimed the fortress was now completely abandoned and all of its valuables stolen, and the settlers within were wiped out.

However, Kassandra knew the truth. Altaïr Ibn-La'Ahad, the late Mentor of the Levantine Brotherhood, would never allow the Assassins to fall, so he devised the plan to spread his teachings worldwide to keep the legacy of the Hidden Ones alive.

Kassandra won't deny that it is something to admire since she was considered one of the early precursors to the Assassin Brotherhood. Still, she knew their enemies, the Templars, would do the same, thus continuing the endless war that she knew would last for centuries or beyond.

But that wasn't important. What's important is what she had discovered, what Altaïr left behind deep beneath the castle. She had found the locked door of Altaïr's Library. Granted, she knew it was not her place to look inside, for it was meant for someone else. But what got her attention was etched on the door's sides.

An Isu script.

Kassandra didn't know if Altaïr intentionally or unintentionally placed them there, but she knew these scripts were there for a reason. After taking the time to decode them, she learned of the secret location of a hidden library that contained the Voynich manuscript.

Knowing that this information could benefit the future, Kassandra took a year to travel to Baghdad, only to discover that the Mongols were ready to invade.

With the situation, she couldn't risk revealing herself, so she did the craziest thing to get to Baghdad. Purposely getting herself hurt, making it look like the Mongols attacked her.

And it worked almost too well when she threw herself in front of the injured guards to make it more dramatic/convincing.

And that's how she got in.

"The things I do for the future…" Kassandra tiredly sighed as she dawned herself with Baghdad armor making her look like one of them, hiding her feminine appearance and a helmet hiding her face. She is armed with the Staff of Hermes on her back, a sword on her right hip, and a dagger on her left hip. "Now, to find that secret entrance."

The immortal Spartan slowly peeks her head out of the tent, checking if anyone is around or if any guards will notice her. Thankfully she was in the clear. She walked out of the tent and then headed deeper into the city of Baghdad.

The Spartan calmly walked through the streets filled with soldiers and injured or concerned civilians. It saddened the warrior to see all these people in this state, but she knew that it was not her place to intervene, and above all, she had her mission to fulfill.

After a time of walking, she finally made it to the very spot she was looking for, an empty secluded dead-end within the streets of Baghdad.

"Here we are." Kassandra sighed as she looked around the location. "The coordinates should be around here."

The Spartan carefully looked around but saw nothing to her slight annoyance until she remembered her hidden talents.

Eagle Vision.

Granted, her Eagle Vision was unique since she could see through the eyes of her beloved eagle, Ikaros, may she rest in peace, but like the selected current civilization, she too can see what ordinary people can see.

She began seeing the world in black as she focused on her senses. Then she carefully looked again until she found a particular spot that glowed yellow.

"Hello… what do we have here?" Kassandra mused as she walked closer to the middle of a secluded area where the spot while dismissing her Eagle Vision.

Inspecting the spot, she noticed a small opening, a hole, that seemed big enough for a butt of a staff to insert in.

"Well… I wonder what to do?" The Spartan joked as she took the Staff of Hermes behind her back. Then she used the end of the butt of the staff to insert it in the whole until the staff reached the end, then instinctively turned the staff to the right until a clicking noise was heard.

Then suddenly, the ground slightly shook, and the land where the staff is began opening up like mechanisms than a stairway leading down to where a glowing blue light was shown as a guide.

"Love how the Ones who came before like to make their dramatics," Kassandra sarcastically says, already getting used to how they would leave these secret chambers and advanced technology.

The Spartan took back the staff and placed it back on her back, then began her descent towards the secret door.

Not aware that a shadow of a person watched the whole thing not before following the Spartan.

Kassandra descended downward on the stairway until she reached the flat surface. She then looked around, seeing a large chamber underneath Baghdad. The room mainly showed streams of blues light lighting the entire room but what was more eye-catching was the big door in front of her.

"Here we are," Kassandra said as she approached the door. As she walked, she couldn't help but feel that this place was similar to Altaïr's Library, not behind the door, mind you, but similar in the way.

"Did perhaps the Apple that Altaïr had in his position inspire him to build that secret room beneath Masyaf?" Kassandra mused as she was up close to the door, having a good look at it. "Now… how to open it…"

Kassandra looked hard until she didn't find anything, no locks, no form of key slots, or any writings for a hint. It was just a stone door, much like the one in Masyaf. That was until she decided to use her Eagle Vision to see anything hidden. And what do you know? There were writings on the door.

"Alright! Now we are getting somewhere." Kassandra smirked and then closely read the message. "A poem…? No… a riddle." Kassandra says as she reads the hidden riddle out loud. "To open the door to seek what you find, you must say the word that defines all time. The one who sees the past, the one who sees the present, the one who sees multiple future endings. Who am I?"

Kassandra was honestly baffled when she read the riddle. She had no idea what it could mean. It could be anything! 'What is this?! Malaka! Who writes such a crazy–! Wait… the future…'

At that moment, she then recalled a specific relic during her time facing the Cult of Kosmos.

The Pyramid.

A lifetime ago, after the bitter battle against her brother, Alexios, and wiping out the Cult. She recalled when she and Aspasia, a Cult defector, were summoned by the Pyramid through her father, Pythagoras, to return to the Sanctuary of the Kosmos before destroying the pedestal that powers the Pyramid so it can never be used again.

During that time, she used the Pyramid to look into the future. She saw the Assassins, their goals and ambitions, and Ezio Auditore da Firenze but she saw even more profound, far deeper. And there he saw him. The young Assassin of the 21st Century. The one who fitted the riddle and what became of him in the end. Thus, Kassandra uttered the very words to answer the riddle.

"The Reader." The moment she said those words, the door began to slide upward, opening itself, indicating that she had the answer correct, showing a dark room before her.

'Thank you, Desmond.' Kassandra smirked, mentally thanking the future Assassin as she slowly walked into the dark room.

As she entered, all she saw was black until the same blue streams of light glowed throughout the walls of the inner chamber beyond the door shone, brightly for the room to lit up, showing the entire room filled with scrolls, books, and journals of all kinds you would find in any library.

Kassandra knew that each of these forms of wisdom had its value and secrets, but none of them were what she was looking for.

She found what she was looking for on a pedestal in the middle of the room.

Kassandra walked closely to expect the pedestal. As she did, she took off her helmet and dropped it to the ground. She smirked, finally finding what she had been seeking.

"The Voynich manuscript." Kassandra whispered in awe as she took in full detail of the closed book that held Isu language on the cover of the front of it. Not many people would understand it, but she did.

She slowly reached out for the manuscript with her right hand, but she sensed someone behind her before she could. Without a second, the Spartan grabbed the hilt of her sword in a reverse grip, then she lowered her grip downward and moved it slightly to the left, making the tip of the blade behind her move the point of the sword upward behind her back earning a sudden gasp from her line of sight behind her.

"Impressive. I almost didn't sense your presence… Assassin." Kassandra smirked as she turned her head back to see who it was, and her eyes slightly widened at who it was.

It was Darim Ibn-La'Ahad, the son of the legendary Assassin Altaïr Ibn-La'Ahad.

"Darim Ibn-La'Ahad, you're a long way from Egypt." The Spartan said, earning a shocked expression from the said Assassin.

"How do you know me, woman?" Darim narrowed his eyes while keeping a safe distance from her knowing that the woman before him wasn't what she seemed.

"I am Kassandra, and how can I not know you? Knowing who your father is, it is not strange to know who you are." Kassandra says as she turns around and lets go of her sword, chuckling at Darim's expression. "I am here for reasons of my own. If you believe that I am Templar, then you are mistaken."

"How do I know you are telling the truth?" The Assassin asked, still skeptical of her.

The Spartan just chuckled before turning around and taking the manuscript and began reading it while her back was facing Darim.

"For starters, even with the weapons I hold, I am defenseless, and I believe it is one of your tenants, isn't it? 'Stay your blade from the flesh of an innocent'. I believe I have not warranted a reason for you to kill me, yes?" Kassandra simply said as she looked through the pages of the manuscript.

Darim was silent but did not deny the truth about what she said, granted he did find her suspicious and was going to interrogate her for answers. But seeing how she is acting, his Creed demands him to do the right thing.

"That may be… but that does not change the fact that you are here," Darim said, pointing out that fact. "No ordinary person should be able to find such a place as this."

Kassandra chuckled at that logic. "Please. Did you honestly believe that the Assassins and Templars are the only ones to have to learn the existence of the Ones who came before? It would not be strange for people like me to learn of their existence. After all, past stories should hold those suspicion, like the Apple."

"You even know of the Apple…?" Darim questions, more cautious of her.

"I know only what I need to know," Kassandra says before finally finding the page she was looking for in the manuscript. She carefully tears off the page without making a sound while speaking to cover the noise. "But you should know that we have one thing in common."

"And what would that be?" Darim questioned but was surprised to see Kassandra turn around to face him while handing him the manuscript, not noticing that the Spartan had folded the torn page and hid it in one of the sleeves of her armor.

"We both want a brighter future." Kassandra smiled as she handed the manuscript to Darim, who was hesitant but slowly took it from her and examined it and its pages before looking at her again with a raised brow.

"Why are you here?" Darim questioned.

"Knowledge. The same perhaps for you." Kassandra answered truthfully. "I already learned what I need from the Voynich manuscript."

"But it is encrypted." The descendent of the Hidden Ones pointed out as he carefully looked through the pages of the manuscript.

"I have a good memory." The Spartan shrugged, saying a white lie but now was about to seal the deal. "Listen… I know you are still suspicious of me, but I have already learned what I need, and look! You now have the manuscript in your hands. Without a doubt, it will serve your Brotherhood well, yes?"

Darim was in deep thought as he laid out his options. True, he now has the manuscript after learning it from his father's studies. But he did not expect the woman, who at first was a man due to her armor disguising her as a man, before him to discover this place first and simply hand him what he was looking for.

With deep consideration, he had made his decision.

"Very well. I have found what I was looking for. Thank you." The Assassin nodded in appreciation while placing the manuscript in his robes.

"Excellent!" Kassandra said as she kneeled, took the helmet from the ground, then stood up and wore it back on her head. "Then let's be on our way. A war is coming, and I would rather not be a part of it."

Darim did not question it but knew that it was true.

The two walked out of the room and then headed towards the stairs while the lights within the chamber slowly dimmed, indicating that there were no people in the room. Then, finally, the room returned to darkness.

As the two slowly descended the stairs, they were greeted with something they did not expect.

A dozen armed men blocked their way—most wore the same armor as Kassandra.

As the two walked out of the entrance, the door behind them immediately closed.

"Friends of yours?" Darim asked the Spartan next to her while not looking away at the possible enemies.

"I was about to ask you the same." Kassandra replied as she gestured at a few of the men that were wearing black robes.

As the two ready themselves for a fight, one of the men in the black robes and, interestingly, has heterochromia, took a few steps forward. "Darim Ibn-La'Ahad… so it is true. You live. And I would assume the rest of your kind has as well."

"You know me, stranger?" Darim questions, knowing who this person is possibly associated with, as he holds the hilt of his sword and Kassandra holds her dagger.

"Who does not, Assassin?" The man spat as the guards pulled out their swords, ready for a fight. "Our spies have seen you were wondering about within the walls of Baghdad. At first, I thought it was a mistake, but it was a risk we could not take."

"So there are Templars within Baghdad." Darim states. "No doubt you played a role in this chaos."

"Yes, our order has reached this far as well." The man chuckled. "And your service is most appreciated."

The Assassin and Spartan looked at each other in confusion, then back at the Templar.

"What are you talking about?" Kassandra questioned.

"For bringing back the Voynich manuscript from where you came from." The Templar said, making the two widen their eyes in shock.

"How do you know that? No one else should know of this place." Kassandra questions, it may have been a year, but no one except for her, Darim, and possibly Altaïr should know of its existence.

"You are not the only one with hidden knowledge." The man chuckled before glaring at the two while hounding his right hand. "Give us the manuscript, and I might just let you two live."

There was a tense silence between the two groups, not moving from where they stood until Kassandra broke the silence.

"How about… No." Kassandra answers before quickly throwing the dagger toward the Templar's head, but in a split second, he evades the shot. However, the blade stabbed one of his men behind him, instantly killing him.

"KILL THEM!" The Templar shouted as his men charged.

Darim quickly drew out two of his throwing daggers and threw them toward the two guards by the neck, instantly killing them.

Kassandra draws out her sword and charges toward her enemies. She blocks one of the guard's swords with hers, then pushes it away while following up with a slash, cutting down the guard. Then she ducks down, avoiding another sword strike from another guard before she charges toward him and then stabs him with his sword killing him right before kicking the corpse away to face the other guards.

Darim had already killed two more of the guards thanks to Twin Hidden Blades. He quickly draws out his sword and expertly kills two more guards while avoiding their slashes as he counters with his own.

The Templar leader growled. Seeing that most of his men were dead, he turned to one of his remaining Templar followers. "Get reinforcements, NOW!"

"Y-Yes, sir!" One of the Templars said as they both ran to get help.

"Stop right there!" Kassandra shouts after she kills one of the remaining guards. Then was about to give chase but was blocked by the Templar leader.

"You will not escape!" The heterochronic Templar growled as they clashed blades with each other. "Who are you, interloper?"

"Wouldn't you like to know?" Kassandra snarky says as she kicks him in the chest, gaining a few distances from each other.

The Templar growled and was about to charge, but then a sudden pain in his left side. He quickly checked to see that it was a knife deep in his flesh. He quickly looks up to see Darim with an extended arm, indicating that he threw it and that all his men are dead.

Before he could do anything, he heard shouting, making him turn to see that Kassandra was charging at him. Before the Templar could act, it was too late. The Spartan stabbed right in the stomach, gasping in pain and dropping his weapons.

Before he fell, Kassandra quickly grabbed him and gently placed him on the ground while Darim walked up to the dying Templar.

"It is over, Templar." Darim says as he kneels towards the dying man.

"So… it is… a shame…" The Templar breathed in and out. "A shame… I will not be able to learn… the secrets of the manuscript…"

"Whatever secrets it holds, it is not meant for the Templars." The Assassin said but then raised a brow when the Templar chuckled while coughing a bit.

"You… misunderstand, Assassin… it was never for the Templars… it was for my own gain…" This got the two in confusion.

"What are you talking about?" Kassandra questions, not understanding what this man is talking about.

"It… does not matter… in fact… it is not of your concern…" The heterochronic Templar said as his life was slowly dwindling away. "I am but… an Instrument…"

"Instrument…?" Darim questions as he turns to Kassandra but is equally confused as he is before turning back to the dying man. "What do you mean?"

"It does… not matter… I was… born too soon…" The Templar says before he utters his last words before dying. "If only… I had… more… time…"

"Though your confession was confusing. I pray that you will find your answer in the next life." Darim says he closed the dead Templar's eyes.

Before Kassandra could say anything, suddenly, the two heard the sound of men approaching them.

"We need to leave!" Kassandra says as she stands up, followed by Darim, who he nodded in agreement.

The two quickly climbed up the walls of the secluded areas, and as they reached the top, they parkoured their way out while avoiding any guards.

Almost the whole day passes, and the two are finally out of the city's walls, thanks to Darim knowing the way out.

They could rest as the two were finally at a safe distance.

"Well, that was an interesting experience." Kassandra says as she removes her helmet.

"Perhaps." Darim says he gazed back into the city, which the Spartan noticed.

"You are going back, are you?" Kassandra questions which the Assassin answers with a nod.

"Yes," Darim answers, not turning away from the city. "Now that I know the Templars are here, I must do what I can to help these people."

"I see… do you require aid?" The Spartan asked.

Darim shook his head and then turned to the woman with a smile. "That will not be necessary. I believe I know what I need to do from here."

"If you say so." Kassandra says, then noticed that Darim offered his hand, which she took and shook.

"Thank you for helping me, friend." Darim says in appreciation.

"Best of luck to you and your Creed." The Spartan said as Darim nodded, then walked away, leaving her behind. As she watched him go until he was out of her sight.

With her lonesome, she takes the page she tore off from the manuscript from her sleeve, then unfolds and takes a good look at it.

Kassandra sighs and looks up at the sky. "Hopefully, this page will help those who need it in the future."

The immortal Spartan looked at the sky as an eagle sore over her and screeched as it flew high in the sky while the sun began to set.

To be continued…