Garp the legendary hero of marines was currently laying on the floor in pirate island after fighting his former pupil kuzan and other pirates there . Garp came came to pirate island for rescuing his current pupil Coby with sword squad members. For him they were they are future of Marines , so he stayed behind to insure there departure .
Garp distroyed a very large portion of Island and crushed the pirates like he was nor retired and neither old but still there was limit to how much you can do things and he was currently getting Frozen while having a piercing wound in his stomach .
But he was not sad from his current state because he have secured the young marines and saw Coby realising his own potential. Garp knew if there was ever his end then he didn't wanted to have regrets in his life but their still were some regrets left like Ohara incident , Ace death. He wished he could have done something about it .
He tried to live his life as much without regrets but there always some left ,Guess that was fate. Garp used his mini transponder snail to give a message to Marine vessal " This is Garp , Mission to rescue captain koby is complete . " Tashigi asked him to come back quickly so they can leave but garp said them to leave island at full speed and he will manage on his own and there safety is top priority here because they are the future of Navy .
Slowly his body was getting Frozen but he was not worried just happy that they were safe and was laughing while laying on ground but suddenly his body started to shine , Garp thought ' what this light ??' . Shriyu asked to kuzan " what is happening with him ?? " Before kuzan could say something the light went of and there was nothing in place of garp body .
Shiryu panicked at this and ordered his men " Even ,I know that garp don't have eaten devil fruit . So, it must be someone nearby , find him or cammador teach going getting angry at us for letting koby getting away form us !!"
The next day headlines spoke of safe return of Navy's young hero koby .....
.... The disappearance of legendary hero , Vice admiral Garp at pirate island.
MHA world :-
Garp was currently laying on a bed inside a small apartment . The moment he woke up his thoughts were that he will be in some kind of chain but he was in bed . It confused him but he remembered what happened and light that shines from his body before he went blank . It meant someone rescued and he was little angry that those kids didn't listen to and came back for but then he saw the room it was nothing like room that would be in marine base or ship .
Then he looked at his stomach and he didn't felt pain from that stab or any other injuries . His body felt little weird like he was not old anymore and felt super energetic . He decided to find mirror and looked his in it . What he saw was maybe not most bizarre thing saw in his life but it definitely become one top ten .
Currently he was looking at his own fourteen years old body . Garp even Punched himself thinking it was some weird dream but it was reality . He rushed outside to see where he was but all he was saw big building's like the one kizaru said were on egghead and he thought he was there but scrapped that thought since he saw the pictures of that place and this was definitely big building's but didn't looked like the one at egghead .
He understood that he was definitely at very foreign place from back home .
( Listen kiddos , yes I am doing a new fanfiction and this one will continue because garp is my favourite character I'm one piece and he could definitely fit his own way in MHA world . So , let's see what this legendary hero does in World hero's.
Note : garp is in his teen and not prime because it would be really unfair to throw this dragon in world of rabbits. So , he is strong than most hero because of his experience ,fighting and haki knowledge . He don't have quirk but his strength would be considered one and don't worry you will see him get super strong again but through intense training . And he might see deku as a kid like koby because he is like carbon copy in some way will help him time to time . He will have is carefree attitude here too and might be little books focused since he know nothing how this world work and it's history )