Few things before I start this story.
One this is a Hit trains Natsu story so no Goku or Vegeta won't be in this story neither will any other Dragon ball super characters but maybe a few References.
Second Natsu will not be godlike and time-skip Molotov everything that pisses him off. But powerful ,cold, indifferent? Yes. I'm thinking that he will be just above the level Erza maybe on par with Laxus but below Gildarts
Hit will be an on and off character as you now hit is an assassin goes place to place killing his contracts so he won't be in this story other than references or flashbacks.
Will Natsu join fairy tail...yes...Now before you outrage Natsu won't be an assassin in this story. he will have timeskip but he won't attack vitals like hit does.
Natsu will have a second form of magic when he's not using timeskip which will be wind magic with a sword, because he can't always rely on timeskip now can he?
Now let's see how far this story will take us?
(Universe 6 – Unknown Place)
It was pitch black outside. Cars clouded the streets while the news constantly told people to watch out for the fugitive Frost. Somewhere on top of a building a man stood on there he wore a long dark purple and grey coat with gray pants held together with a blue belt and yellow buckle. He was tall but muscular his skin was purple but has impassive red eyes that bore into the soul of his enemies. The man raised his hand to look at the next contact.
"Hmm a man that goes by the name of...Zeref." A smirk crossed the mans face as he disappeared within the night.
(Universe 3(1) Fiore age x770)
A black haired man was meditating on the ground, his brow furrowed almost as if he's frustrated by something. The man stood up and opened his eyes, turning his head he saw the infamous assassin staring right at him.
"I wouldn't suggest coming near me unless you want to die" Zeref said while looking at hit unflinching.
"My name Is Hit and I was sent to kill you. This will end in one punch." Hit said while preparing to throw his arm out.
'what is this fool doing? He meters behind me his hand can't reach that f-' Zerefs thoughts were interrupted as he suddenly felt pain before he fell down dead.
Hit put his hand down and started to walk away until he heard "Death Predation"
Hit sensed immediate danger and teleported out of harms way. The large death wave killed everything it came contact on to causing hit's eyes to open wide as that power.
Zeref then calmly looked at hit who was still in the air. "I don't know what kind of attack that was but I haven't felt pain in a long time. Who are you?" Zeref asked with narrowed eyes. Maybe just maybe he could gain something in his favor.
Hit landed down on the ground surprised at how Zeref was still alive, he hit him with enough force that his Heart should've stopped. But that surprised face left as soon as it came creating the once emotionless man he was.
"I've told you my name is Hit, I was sent to kill but what I wasn't aware of was that you would survive that attack hit your heart to cause it to stop beating, how are up I know you did not restart it or I would have felt something." Hit said with suspicion in his voice.
Zeref looked momentarily stunned, he thought everyone in fiore knew of the black wizard, he figured this must be a newcomer.
"your strong I'll give you that but your killing techniques won't work on me, for I am cursed with immortality by the god Ankhseram. And on top of that I have a healing factor that heals me in seconds.
Hit instantly became on guard, if this man was immortal and really did have a healing factor like he said he did then this would be a problem as his attacks targeted the vitals.
'Hmm lets try something' Hit then rushed to his opponent and activated his timeskip and attacked Zeref with a full on assault of punches hit every part of his body, vitals and non-vitals alike. Finishing the move with a final punch to the gut Zeref was sent flying back in a shout of pain he landed head first on the cold ground. But just as hit predicted Zeref got back up healing himself instantaneously.
"So it is true you are immortal, I don't believe at this time I will be able to kill you" hit said with a hint of frustration at not being able to kill the man. He started to leave but heard Zeref speak.
"wait, how about we make a deal that would benefit both of us." Zeref said with a sly smirk.
Hit turned back impassively and simply said "I don't make deals" but then what zeref said stopped hit from moving.
"what if I could send you to a person that could kill me" Zeref said cryptically.
"what are you talking about fool, if your immortal and have a healing factor then how can you be killed?" Hit said angry and confused at this man.
"Look ,I after I was cursed with immortality, Ankhseram made it so a certain person would be able to nullify my healing factor and would be able to bypass my immortaliy, killing me in the end, it was part of the curse of Ankhseram he said there would be only one way for me to die and that would be by my little brother. So how about you train him into your arts and he can kill me" Zeref said with a smirk.
Hit thought carefully before deciding not to. "hmph give me a reason why I should even think about training some brat with my techniques with his measly power." Hit said with an added glare.
"think of it like this. If My brother kills me then that means you wouldn't have failed the contract and you get to help someone out of the goodness of your heart" Zeref said with a sarcastic at the end.
Hit was thinking...thinking very hard on the subject. On one hand if he did train the brat then he would have passed the contract as there was no time limit on there And his reputation would not be ruined but on the other hand he would have to train a snot-nosed brat who probably couldn't even count to 5...BUT! If the brat could get stronger than his expectations and train with him, then the assassins power would increase two-fold! In the end hit relented and asked to where to find this brother of his.
"His name is Natsu Dragneel his whereabouts are a few miles north in the woods you can't miss him because he has distinctive pink hair." Zeref said. While hit teleported away.
(Universe 3 – Fiore's woods)
Hit was walking around looking for a Pink haired 4 year old in these thick woods...yeah not hard.
(skip – 3 hours)
Hit was getting frustrated he was close to blowing this whole forest to smithereens had not been the fact that he needed to find this child.
As his was walking he saw a camp fire, he figured no one would recognize him so might as well ask around for a pink haired brat.
As he came closer he finally found the pink haired kid sitting on a log cooking a piece of fish.
"uugh I'm starving I want to eat this now!" Natsu yelled at himself causing Hit to step out to talk to the boy.
"you are Natsu dragneel correct" Hit said with his usual Impassive face.
"y-yeah I'm natsu and who are you!" Natsu said slightly scared at the arrival of the assassin that appeared out of nowhere.
"relax your brother sent me to find Dragneel" Hit said
Natsu looked shocked for a moment before he ran over to the man jumped around.
"really! Where is he? Will you take me to him? What does he look like?!" Natsu asked while jumping around frequently.
Hit looked bored for a moment before answering the energetic child.
"your brother sent me to train you in the art of my attacks so you could help him with a certain problem but I need you clarify somethings before I start to train you Natsu." Hit said as he decided to test the young kid before he decided he was worthy enough for his techniques.
"Okay what do you need to know mr stranger!(2)" Natsu said causing Hit to raise his eyebrow a little.
"what's your dream for the future young Natsu" Hit asked
Natsu thought long and hard for a second before answering.
"I wish to find a family with lots of friends that I can protect but also I wish I could find a strong rival that I could have an ultimate battle with." Natsu said looking excited at such a future
Hit looked momentarily surprised at those words as they reminded him of a certain care-free saiyan. Hit smirked and motioned for natsu to follow him.
"alright Natsu you won't Fiore in a awhile so come" Hit said grabbing Natsu's shoulder and teleporting away not to see Fiore for a certain amount of time.
(1) I had to make a sort of universe for fairy tail to be in to make the story kind of compact together
(2) He four years old with no one teaching him anything about staying away from strangers and stuff
Alright guys this is the end of the first chapter, I hope I didn't rush this to much, because I was trying to create a steady pace.