Disclaimer: I don't own Attack on Titan, Devil May Cry or any of its characters…

A long time ago, there was a war between the human world and the underworld. While different tribes and races on Earth had made enemies with each other, the demon world was a bigger threat than anything they could have imagined. Humanity seemed to have lost all signs of hope when the almighty MUNDUS, the king of the underworld, invaded the human world with his army of demons.

But despite all this, there existed one small beam of light in the dark future humanity faced. One demon took up arms against his own kind and fought for the humans. His name was SPARDA, the greatest warrior in the underworld and whose power is said to be equal to Mundus. He alone battled against the armies of the underworld and pushed them back into their domain.

Sparda used the blood of a virgin warrior to seal the gates of the underworld, before sealing Mundus away on Mallet island at the cost of his powers. For more than a thousand years, Sparda walked the Earth as a protector of humanity and became a legend, until he met a woman who would change his life and give him everlasting happiness. Her name was EVA, and from the moment he met her, Sparda ultimately fell for her. In turn, Eva accepted and saw the goodness in him.

A few years later, Sparda and Eva married and lived happily together. Eva soon gave birth to twins, namely Vergil and Dante. Sparda became happy that he experienced what it felt like being a human but nothing lasts forever.

Seven years after Vergil and Dante were born, Sparda and his family were attacked by demons sent by Mundus, who noticed the seal was weakening, in order to kill the traitor and his family. This event lead to the death of Eva as she was protecting her sons while Sparda fought them off, but was too late to save her. Sparda was eventually able to get his sons to safety but was gravely injured as a result, further weakening him.

Both Vergil and Dante who witnessed the death of their mother swore vengeance on that day. Meanwhile, Sparda realized that his time was running out, trained the twin brothers with both his legendary weapons for the next seven years. He gave the YAMATO, an O-shaped katana that can cut through dimensions to Vergil while he gave the REBELLION, a broadsword capable of awakening demonic power to Dante. Eventually, Sparda spent his final moments with his sons. He gave them one half of their mother's amulet each, as a final memento and told them to forge their own paths in life.

After Sparda had passed, they buried him beside their mother in Redgrave and began to hunt for the demons responsible for the deaths of their parents. A year after their father's death, at the age of fifteen Vergil began to change after he and Dante left together. He began to absorb the power from demons he killed which led to him craving for more.

The brothers had a falling out when Dante found out what Vergil wished to attain as they fought over their ideals. They fought as if they were lifelong enemies, taking twisted pleasure in the feeling of fighting each other. The victor was Vergil, who unknowingly awakened Dante's Devil Trigger after getting stabbed with his own sword. Before Vergil could deliver the killing blow, Dante fought back with his new form but was not strong enough to defeat hiss brother.

After that battle, both brothers went their separate ways until they met again four years later, at the age of nineteen. The brothers reunited and joined forces with the Walking Arsenal LADY to stop her father Arkham who wanted to use their blood and amulets to gain Sparda's power and awaken the Temen-ni-gru, a tower that served as a portal to the demon world.

Vergil and Dante defeated Arkham and stopped his plans, before having one more battle in the tower in which Dante came out as the victor, but lost his brother as he fell into the underworld. After the battle, Dante started his business DEVIL MAY CRY to hunt demons and protect others.

Four years later, Dante was approached by the Lightning Devil TRISH who told him that the sealed Mundus was beginning to break out on Mallet island. Dante accepted the job and went to the island in order to stop Mundus. It was there that he ran into a servant of Mundus named NELO ANGELO and fought him as he tried to stop Dante from resealing Mundus, but ultimately failed.

After defeating Nelo Angelo, Dante realized it was his brother whom he was fighting all along. Nelo Angelo was then sent back to the underworld for his failure. Dante finally came face-to-face with Mundus after learning that Trish was working for him and used her as a hostage to defeat the son of Sparda.

Dante freed Trish and used the amulet he got from Nelo Angelo to awaken the Force Edge from its sealed state, becoming his father's greatest weapon, the DEVIL SWORD SPARDA and using it to battle Mundus. Dante defeated Mundus and sealed him again. Mundus' defeat led to Vergil becoming free of his control, but was still trapped in the underworld, so he waited patiently for a portal back to the human world. Trish joined Dante in his business, becoming his partner in devil hunting along with Lady.

Three years later, Dante was called on again to stop a madman by the name of ARIUS who wanted to open a portal to the demon world and absorb the power of a demon that rivaled Mundus' own. Its name was ARGOSAX. Dante joined forces with LUCIA, a woman with a complicated origin who wanted to kill Argosax.

Arius was successful in gathering the items required to open the portal and was waiting for the day of an eclipse to complete the ritual. After opening the portal, he was defeated by Dante who realized that the dimensional gap cannot be closed until Argosax was also defeated. Dante and Lucia argued on who would go fight Argosax which led to a coin toss where Dante won. Lucia later figured out it was a double-headed coin.

Unknown to them, Vergil sensed the portal and used it to escape the underworld while Dante was still fighting Argosax as the gap closed. A few months later, Dante got out and got contacted by Vergil, who wanted to meet up and discuss what happened.

Vergil told Dante that after he fell into the underworld, he immediately ran into Mundus who defeated and corrupted him into becoming Nelo Angelo. Dante finally realized that while Vergil went power hungry, all he wanted was to be able to protect what he cared about and that he never wanted to feel helpless again when their mother died.

Both brothers went their separate ways again with Dante returning to his job as a devil hunter, while also growing closer to his partner, Lady. Vergil turned down an offer from Dante to work with him in Devil May Cry as he wanted to find a new way of life. Two years after Vergil left, he met a woman in his travels named ANNE YEAGER in the continent of Marley and they became friends, which later turned into love as they got together a year after their first meeting.

Vergil later told Anne about his history and what he had done. Anne was shocked and a little bit afraid but pushed it aside since her people didn't know better. She pushed those thoughts aside and accepted Vergil for who he was, and she never judged him for the choices he made.

The two moved to a comfortable place in Redgrave so that Vergil can visit his mother anytime he wanted to. They received letters from Anne's family in Marley but they made sure to answer all of them back. Two years later, Anne gave birth to a child that bore his father's white hair and his mother's green eyes. Vergil sensed a large amount of demonic power manifesting in the child's arm, but he pushed that aside for now. They named him Nero.

Dante made sure to visit his brother, dropping by to tease the once power-hungry man about getting a girlfriend and settling down every once in a while. It irritated Vergil but made Anne laugh all the time. He also made sure to 'remind' his brother that Uncle D would teach Nero how to appreciate pizza and strawberry sundae, leading to Vergil chasing Dante around many times with an intent to kill. Dante, at this point, had gotten together with Lady and were expecting their first child in a few months. But then again, nothing lasts forever.

Vergil began feeling traces of his corruption as Nelo Angelo coming back to him, making him fear for the safety of Anne and his child. He tried suppressing in his mind, but Mundus' power was beginning to overwhelm. Vergil couldn't even get proper sleep at night due to how his nightmares were getting worse.

It reached the point where Vergil quickly contacted Dante to help him out before it was too late. While he waited, Vergil distanced himself from Anne and Nero, much to her confusion. He simply told her that everything would turn out fine.

Finally, the corruption became strong enough once more to have Vergil switch with Nelo Angelo in his place, as a split personality of sorts. Nelo Angelo told him in his mind that the war isn't over yet and that Mundus will return to kill every being that bore the blood of Sparda. Vergil internally pleaded for Dante to come and help help him but it was too late. Under Nelo Angelo's control, he slaughtered Anne in their home and was about to go for Nero next, but Vergil managed to fight out and regain control to save his son.

Dante arrived at Vergil's home to see his brother crying over the loss of his lover while blaming himself for what happened. Dante became angry with himself too, he should've arrived here sooner to help his family. Vergil then handed Nero to Dante after his cries, entrusting his son to his brother as he created a portal to the underworld with the Yamato, determined to avenge Anne and kill Mundus for what he's done to his family. Before leaving though, he told Dante that if he doesn't come back, the Yamato will be sealed in Nero's unawakened arm to keep it safe from demons and to give the child something to defend himself when he grows up.

Dante tried to stop Vergil but was unsuccessful, and he could only fulfill what his brother wanted him to do. He went back to his agency, only to see it in total ruin. He quickly set Nero aside and checked everywhere for Lady and Trish, tears already in his eyes as he feared the worst.

He could only cry out in grief when he saw Lady on the ground, killed by slitting her throat while Trish had a massive hole through her stomach, which she couldn't heal from. Lady was due to give birth just a month from now. Dante was then caught off guard when he was stabbed with the Devil Sword Sparda from behind, piercing his heart as he noticed a bunch of demons invading the place.

Just when the demons were closing in on little Nero next, Dante transformed into his Devil Trigger and laid waste to all of them. After that small altercation he was wondering why he hasn't healed until now, but then he figured out that it was his father's weapon that pierced through him, which gave him his red flag.

Dante needed to quickly find a place where Nero can stay safe from the demons as he remembered a place that Annie, Vergil's lover, once told them about. It was a small island to the west of Marley called Eldia, which had three gigantic walls protecting all of the people within it. Ignoring the part where Anne said that ruthless beings called 'titans' roamed the lands outside of the walls, Dante flew towards Eldia in his Devil Trigger state with Nero, using every ounce of his power to prevent himself from turning back into human form.

Finally reaching the island of Eldia, Dante saw the titans walking around everywhere and he could only shake his head. Looks like Anne wasn't kidding. Demons were one thing, now these titanic bastards? Nero will have major headaches when he grows up. Oh well, their kind was stronger than these pieces of shit any day and Nero could whoop their asses easily if he goes through the proper training like he did.

As soon as he reached the big wall, he transformed back into human form and had to regain his breathing since he spent too much of his power flying all the way. Dante felt himself getting even weaker than before, so he had to find a family who can take care of Nero, quick.

While looking for a house where he could leave the basked where Nero was in, Dante could only be confused as the people here were acting like, natives, or something. Everything around here was old school, something that he took notice of. Did they even know about technology? Anne never mentioned anything like this before. Plus, the people here were looking at him and at the clothes he was wearing. Seriously, people? His style was something fashionable these days! They must be falling behind or what! Something was definitely wrong here, and if he could, he would look into it and see what's wrong, if it weren't for the demonic poison eating him out from the inside.

Dante couldn't take it anymore and simply left the basket in the doorstep of the nearest house he could find. A big one with a basement and small tower located at the top of a staircase. Dante clutched his chest as he told Nero that he'll be going to the underworld as well, in order to look for Vergil and kill Mundus with him or die trying. Like with his father, Dante also whispered to the sleeping child that if he doesn't come back, the Rebellion and his two pistols, Ebony and Ivory would be sealed in his unawakened right arm. When Dante noticed that someone was about to open the door, he quickly sealed some of his power into Nero's arm before running off.

The door was opened and a woman came out, immediately noticing the baby on the doorstep. This woman was CARLA YEAGER and she was quickly drawn to how innocent the child looked while sleeping peacefully as she called out to the other person inside the house. Her husband, GRISHA YEAGER answered the call and walked towards her, noticing the baby in her arms. They were a childless couple, because Carla could not get pregnant and the man quickly noticed the smile on his wife's face.

Carla had tears in her eyes. She finally had a child. Sure, she may not have given birth directly, but a baby is a baby. Grisha nodded with a smile as they embraced with the child between them, welcoming the new member of their family. They named him EREN.

That was the tale of the Legendary Dark Knight Sparda and his two sons, Dante the Devil Hunter and Vergil the Darkslayer. This is the story of Eren Yeager, a boy who also carries the blood of Sparda, and a boy who has untapped power sleeping within him.

This is the story of how he will use his power to end two worldly conflicts that have plagued the Earth for over a thousand years.

This is the story of a boy who will grow up to be a legend.

Well, that ends this prologue. Phew! That's one way to summarize things… now stay tuned for next chapter! We'll start things properly next time!

To clarify things, Eren's original name is Nero, and he's Vergil son. In other words, he's simply Nero from DMC, okay? If you have questions, don't hesitate to ask.

Goodbye… and good night! BANG! *too sweet gesture*

-Lance