This chapter happens right after Soul Caliber 3 where Nightmare seals himself in a cave with Soul Edge.
My name was Siegfried Schtauffen but the vial creature called Nightmare took over me when I possessed the soul edge. I have recently expelled that vial cretin but at a cost. I was sent to this new world to earn my redemption. What shocked me the most was the vial creature from the soul edge vanished with the demon from my past but the soul edge turned into the blade of light. I had done what no other person had ever done before, purified the blade that so many had tried to in vain. A powerful wave of power struck Siegfried something vial like the demon in the soul edge but only stronger something that easily corrupts. Then a second wave hit him again almost like two souls intertwined by a bound but it seemed like the second power was being taken over by light instead of being lost in the darkness like the first power was. Siegfried walked towards the power and the two dark powers as he got closer he felt one power turn good while the other was too dark for redemption corrupted to the core like his master. Siegfried saw the evil in both of them but instead of the blond giving up into the demons evil he fought it. While the black haired hair with demonic eyes surrendered into the darkness. Siegfried saw a lot of himself in the blond while he saw his ultra-ego Nightmare in the other boy. As the boys were doing their final blows he got the soul caliber ready for battle to destroy this vial creature. A giant bang resonated throughout the valley walls and Siegfried was ready to strike the black haired kid. The black haired kid started to rise to flee but Siegfried ran up for the final blow. He saw as the blond restrained the final blow to just knock out while the demonic child went for the kill. Something inside of his said not to kill the black haired kid but just to let him go on his merry way. He went over to the kid and the closer he got to the kid the more he saw in himself. The kid was just like him always trying to prove himself and stop something else. He picked the boy out of the water and noticed to his amazement that his wounds were healing on their own. He smiled again and remembered his wounds and healing with the possession of that demon. Realizing the demon had no control over the boy's actions we waited for him to wake while he hunted for wild game.
Almost an hour had past when the boy woke up with a jump noticing a camp fire and the smell of cooking meat on it he immediately started to salivate. Siegfried noticing the boy was awake asked unto him "Boy who are you and where are you from?"
Naruto looked at him questionably and realizing his ascent was not from these parts just said "My name is Uzumaki Naruto and I am from Konoha."
"Well Uzumaki I guess it is customary for me to introduce myself. I am Siegfried Schtauffen I use to be called Nightmare until by some unknown reason I purified the blade you see in my hands. By the way Uzumaki that was a nice battle you fought I think I might take you for an apprentice. I have blades that are similar to my own but none are as powerful as this one. Let's get you home first and foremost I think your friends and family are worried about you very much."
A quick walk through the forest gave way to a forest of bone with only one person in one of the bone spires. Siegfried smiled noticing the young man was still alive and started to chop sections off the bone until the young man was eye level with him. Siegfried said a small prayer and the young man started to stir. Siegfried just said to him "Follow me" Kimimaro followed him without question because he could no longer feel the diseases clogging his lungs. Following the pace they were doing earlier the came upon another place where Tayuya was knocked out feeling mercy for her Siegfried chopped the logs surrounding her legs and proceeded to heal them with the power of his sword. Tyuuya no longer felt the loneliness she had felt for most of her life. Siegfried just said the same thing he said to Kinimaru "Follow me"
Slowly but surely, they made their way back to the hidden leaf village but when they got there all was not as they had planned. Siegfried had hoped for a warm welcoming by his fellow townsmen only to be ridiculed and yelled at for making their precious sharingan go away. A mob started to form while Siegfried drew out his sword for the kill. In one quick motion, he had killed the vast majority of the mob. The villagers started to back away from him while he blasted killer intent while he yelled "How dare you filthy people. That precious "boy" as you call him is nothing but a demon but you try to kill the one who was going to bring him back to you. You people disgust me even more so than ever. I once had a demon controlling me and telling me what to do. You call this boy a demon look in a piece of steel and you will see who the real demons are. Do not ever harm a hair on this boy's head if you even think of doing so you will be dismembered and your pieces will be spread across the wind." The vile villagers quickly fled from the seen not to be in his presence ever again.
The Anbu themselves rushed to the scene and found the mutilated bodies done by a Zweihande type of blade and they rushed to find the man who did this much damage. Kakashi was the first to find the man after he reported to Tsunade about Naruto's new status Missing presumed dead.
His single eye widened as he saw his young charge with a strange man and the same type of sword as what the victims were slaughtered with. Not knowing what to do Kakashi started to charge up a chidori only for the man to block it with his sword. The two battle hardened warriors looked in each other's eyes with a look of loathing till Siegfried said "You will not harm any of my charges, I am just stopping them from getting any more harm, from these vile villagers."
Kakashi did not relent but only pushed further and said "Naruto is one of my two remaining students and I followed my rogue student and Naruto to the Valley of the End but could not find any trace of them, I assume you found him first?"
Siegfried nodded and said "I did witness the last part of the battle and Naruto did not give into his demonic counterpart but the other boy, from what you said was your student, allows his demons to fully control him turning him into a monster."
Kakashi looked down and asked "Is there any chance of redemption for Sasuke?"
Again Siegfried nodded and said "There always a shot at redemption but he must take it for himself."
Kakashi shook his head and said "Come with me to the Hokage Tower and we will work something out. From what I can tell this will not be a pleasant conversation for either one of us."
Siegfried let out a laugh and said "I bet not but hopefully one of these three youngsters will become my students in my art."
Kakashi shook his head and said "I would like a crack at these three as well, the other two are from the sound and could greatly benefit Konoha in the long run, especially with taking out the snake. I bet Orochimaru thinks they are dead so as long as they keep quiet word will not reach the snake in the grass."
The four of them made their way to the Hokage tower and were ready to face the music.