The main character is a transmigrator who got transmigrated to Warring States Period with Garp Template, so he has interacted with all the past legends like Hashirama, Madara, Tobirama, and also the upcoming generations, so most of the characters from the series and other villages recognize him as his reputation as "Hero of Shinobi World" or "Garp the Fist" is famous across the world.
For powers he has all the abilities that Garp had when he was in his prime. He has all three types of Haki (Observation Haki, Armament Haki, and Conqueror's Haki) and Rokushiki. Also, when he was sent to Naruto world, all of these were already at Prime Garp level.
But he also has one overpowered ability that with every passing day his strength in all areas like Haki, physical body, mental strength, increases, so he grows stronger every day passively, even when he doesn't do much training or fighting. His strength, looks, and other traits don't degrade with age and are always in their prime.
Personality wise, he is much similar to Garp and not very edgy like most MCs, and he will be overpowered throughout the story and against majority of his enemies it will be a curb stomp so if you are someone who wants a weak to strong main character, this isn't right story for you.
Since he is from an era where villages weren't even formed, he has no closeness or loyalty towards Konoha or any other particular village. He is just associated with Konoha because he had some positive relations with Hashirama and Madara, and also because Senju clan used to provide him with funds to party, drink, eat, and sleep.
Also, I would like to clarify that Haki in this story will be visible to everyone, as it's boring and dull to write story where Haki wouldn't be visible, especially if the MC has template of Haki man like Garp.
The mc looks like a younger Garp, maybe in his thirties, and has same height and body, but with stronger legs, unlike the chicken legs that Garp has in One Piece. [Image]
A love interest hasn't been decided yet.
MC will know all Garp techniques and also develop few of his own and use them in fight. Some of Garp moves for those who haven't watched one piece are:
Fist of Love: A gag technique. It is a simple but powerful punch used to strike opponents on their head.
Galaxy Impact: Garp infuses his fist with advanced Armament Haki and Conqueror's Haki and then delivers a massively powerful shockwave punch that surrounds an enormous radius, devastating anything in its range.
Galaxy Divide: Garp infuses his fist with Armament and Conqueror's Haki and then delivers a powerful shockwave punch that creates a vertical fissure on his target.
Blue Hole: After hardening his hand with Armament Haki and infusing it with Conqueror's Haki, Garp grabs an opponent by the face and slams them downwards, creating a massively deep hole in the ground as they fall.
Infinitum Explosion: Garp hardens his two fists with Armament Haki and infusing it with Conqueror's Haki at "critical mass", while rotating his right arm, before unleashing a devastating barrage of flaming punches.
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[P.S: It's been long time since I watched Naruto so there will be some inconsistencies with few characters or timelines but nothing major issue as the main events will be covered properly.]