Konoha was a village that was seen as the pinnacle of Shinobi. They have won every Shinobi war and survived the Kyuubi attacking. It was seen that there was no power that can stop them. Then the murders happened...
Within the Leaf Village, there is a park with a statue in the center. It was erected shortly after the Kyuubi attack to commemorate the 4th Hokage's sacrifice to end the demon. The statue is the Fourth Hokage standing tall over the fox demon. It was a treasure to the village so it came to a shock when one morning, the statue was found to be vandalize surrounded by four bodies. The Fourth Hokage was broken off it's pillar and layed on the ground disgrace with graffiti on it that said:
THE DEMON HAS RETURNED!
This angered everyone and so they search for the one that did this. They first thought Naruto was the cause of this but he was spotted carrying the Forbidden Scroll he stole into Kumo. The search for the Serial Killer yielded no results and more people are dying causing mass fear and paranoia around the village. After two months, The total of corpses are 15 civilians, 6 genin, and 2 chunin. The statue that everyone once love is now a source of fear as without the Fourth Hokage statue, the Kyubi now looks like it is waiting to strike, ready to kill at a moments notice.
Team 10, lead by Asuma Sarutobi and made of the Ino-Shika-Cho trio, are walking around Konoha. They were giving a mission to search for a civilian that went missing a week ago and is suspected of being the serial killer's latest victim. They search the poor parts of the village as that was where he was last spotted.
"Ew... This place is filthy!" Ino complains as the area they are searching looks like no one has cleaned it in years. All you can see on the road is garbage and demolished buildings.
Shikamaru just sighs. "What a drag... Ino the area is where the missing person could be."
"That doesn't mean that this has to be dirty! It is not a place for me!"
"Calm down Ino, we just need to find the person and we can go home." The Jonin assures his Genin until they hear screaming. They run into a abandon building and see in the middle of it is a man tied to a chair with a kunai sticking out of his leg. He sees the ninja and yells at them.
"Get me out of here!" Asuma runs to him with his team and begins untying him. As he do that, he hears the captive muttering to himself. "We should've killed him when we had the chance."
"Civilian. Do you know the serial killer's identity?"
"Yes! It was the demon!" The man shouts to the Sarutobi heir who is confuse by his yelling though he has a suspicion who he is talking about. Meanwhile Ino is disinterested at the crazy man while Shikamaru and Choji are looking at the wall of the building. "So what are you looking for Shika?"
"I think this may be a trap. The killer is known for tricking and deceiving his victims." The Nara heir looks at the walls of the the warehouse and sees something wrong. The paint is wet and new so it was brush within the hour. Shikamaru peels some of the paint off sees paper under it. "Wait is this..." His eyes widen as he tries to warn everyone. "It's paper bombs! Get-"
*BOOM*
Naruto is sitting in an outside cafe, hidden under a genjutsu, sees the explosion that engulfs the building. Many freak out and run away but the serial killer smiles and takes a sip of tea as he stares at the flamming warehouse. "I suppose I have enough time for sightseeing. I will pray for your passing."
(The 3rd Holy Grail War)
A young blond man in a black suit can be seen inside a store, looking for a tie. He picks up two, a orange and red. "Hmm. Which one?"
"Assassin! What are you doing?!"
The voice of his master, Zouken Matou, is heard in his head. Naruto sighs at his master. "I told you master, only Lancer and Ruler are left in this war. Your victory is assured we just need to wait for them to kill eachother."
"Enough with your stupidity! By my command seal, I order you to find and kill those two!"
With the seal activated, he is force to walk out of the store though not before stealing the red tie. As he walks away he wraps the tie on his shirt. "By your command master."
Ruler stands with his Einzbern master waiting for Lancer and his master. "Remember to be careful Ruler. Your opponent is the King of Ireland."
"I know master. Though what can you tell me about assassin?"
"Hm..." She tries to remember what information she had. "The Matou family has for generations keep artifacts of the Hassans though from what I heard, they used a different artifact due to summoning you."
"So just like the Einzberns, the Matous tricked the holy grail." Ruler said as he sees the Lancer walking towards them.
"Come Ruler! You shall face the Knight of Ireland." Fionn dashes towards Shirou and hits the Ruler with his spear but luckily he blocks the attack with his katana. They clash together as the Einzbern master runs away and Darnic is hiding behind a tree. The Lancer hits him with the side of his spear, dazing him and then he pierces Shirou. He dodges the attack but his side is hit, grunting in pain yet the japanese hero ignores the pain.
The Einzbern master is searching for the Lancer master, looking around the trees. She focus her vision on wires around the trees. "Ruler! There are bombs!"
*BOOM*
Naruto steps out of a destroyed tree and looks around the demolish field. He sees the Einzbern master pin down a tree trying to claw her way out. He kneels to the homunculus and talks to her. "Forgive me ma'am. Let me make it quick."
*SPLAT*
The ancient serial killer holds his stump as his left arm falls to the ground. He looks down at the master of Ruler and sees her disappear. "Illusion magic?"
Fionn steps forward and points his spear at Naruto. "To interrupt battle, do you have any honor?"
"Honor? Heh..." The Assassin laughs at the concept as his eyes turn scarlet red and pupils become slitted. "Never learn it."
He grabs the knight of Ireland by the neck and slams his face to the ground. Without mercy, Naruto mounts on top of Fionn and punches him again and again with a single fist. He keeps going until the knight's pretty face was nothing but flesh. His body disappear in light, showing the Lancer has been killed. Naruto's eyes go back to heterochromia as he walks away to search for the Ruler and his master. "Greetings Assassin." He turns around and see Darnic standing beside him and grabs his stump arm. "I would like to make a deal with you."
The Einzbern Master and Ruler are running to the target. "Ruler I sense Assassin's Master is nearby."
"Damnit..!" Zouken growls as his command seals are dim, as if it was deactivated. "Assassin! Where are you?!"
The Assassin's Master yells at his servant, commanding him to come and protect him. He sees the Einzbern Homunculus and Ruler coming towards him. The last Matou is then grab by his back and stab in the chest. "W-what!?" He looks behind him and sees Darnic who stab him.
Amakusa's eyes widen at the sneak attack. "AAAHHH!"
The Ruler hears his master yell and looks behind him and is shock at what he sees: His master stab by Naruto.
(Now...)
The Black Faction, Jeanne, Jackie and the Homunculus look at the former master and servant. While Darnic is emotionless, Naruto is smiling. "My my... How splendid. It has been years my old master."
"You as well..." Darnic said as he turns around and walks away. "Let them go."
"Uncle?" Fiore is confuse at the command but the leader of Yggdmillennia explains. "The Homunculus and Assassin is protected by Ruler and her Assassin."
Just like that, the Black Faction leaves though Astolfo gives the nameless kid some words of encouragement.
The four walk to a ledge showing Sieg nature. "It's beautiful."
"I promise to protect you young man. Do you want a name?" Jeanne ask which makes the Homunculus nod.
"I wish to honor the man that save me. I am Sieg." The now name homunculus announces. Naruto whispers to his 'daughter' who walks to Sieg and hugs him. "Come on big brother. Let's go see the animals."
"B-brother?" He ask but she just drags him away. The Ruler and Assassin watch the two pet with deer.
"What is it you see madam?" Naruto question as Jeanne looks sad. "He will be the source of this war. We need to meet the Red Faction now."
Naruto's 2nd Noble Phantasm:
Nine Tail Fox Kyubi- A: Label a demon in the Leaf Village, Naruto not only accepted it he thrives in it. He calls upon the Nine Tails within him and his Assassin class is temporarily change to Berserker status.