One interesting idea could be that Luffy has to rely solely on his Haki and physical training, making him even more of a badass in combat. He might develop unique fighting styles that we haven't seen in the original story where he had devil fruit powers.
Alright, the following is the order of appearance of all the aptitude users and demonic fruits in One Piece:
1 Luffy (Monkey D Luffy)--Rubberfruit (Rubberman)
2. Zoro-Fruit of Swordsmanship (Swordsman)
3. Nami--Sailor Fruit (Sailor)
4. Usopp--Sniper Fruit (Sniper)
5 Sanji-Chef's Fruit (Chef)
6. Chopper-Reindeer Fruit (Reindeer Master)
7. Franky--Boatsmith Fruit (Boatsmith)
8 Brook--Yellow Springs Fruit (Yellow Springs Warrior)
9. Jiro-Murloc Karate Fruit (Murloc Swordsman)
10 Very Fair (Zephyr)-Wind Fruit (Messenger of the Wind)
Renil--Admiral Fruit (Admiral)
12 Chopper, Nami, Usopp, Sanji, Franky, Brook, Jiro-Seven Martial Seas
The above is the order of appearance.
Alright, the following is the order of appearance of all the aptitude users and demonic fruits in One Piece:
1 Luffy (Monkey D Luffy)-rubber fruit
2. Rorono Zoro--Swordsmanship
3. Nami-Sailing
4. Usopp--Gunpowder, Gunpowder Fruit
5. Sanji-Sword Arts
6. Chopper-Ship Doctor
7 Franky-Boatsmith
8 Brook--Yellow Springs Fruit
9 Goronpa Goron--Demon's Wind Kick
10 Rorono Zoro--rubber anchor fruit
11 Reiner-One Piece's Mentor, Devil Fruit, One of the Devil Fruit Ability Users, Sword Master
12 Nami-Author of One Piece, Devil's Fruit, One of the Devil's Fruit Ability Users, the ability user who drew the world map
Well, in the original One Piece, Luffy's devil fruit powers are a huge part of his identity and his combat capabilities. But in this fanfiction, without the devil fruit, his physical strength and Haki would be emphasized more. His fights would be more about pure skill and strategy rather than relying on the strange and wonderful abilities of the Gum - Gum fruit.
😋I recommend the following novels to you:
1. " My Trash Fruit ": The protagonist has the ability of the Devil's Fruit to abolish everything and is determined to become the most awesome leader.
2. " I Abandoned the Magical Beast Seed, Creating the Mythological Era ": The protagonist travels through the foreign world and has the ability of the Demon Fruit. Together with the gods and devils behind him, he creates a mythological world.
3. " Top Grade Demon Fruit System ": The protagonist's pig trotter soul transmigrated to another world, possessing the heaven-defying Demon Fruit System, farming, leveling up, face-slapping, and posturing.
4. " Devil's Fruit Merchant ": The protagonist becomes a devil's fruit merchant, supplying the fruits that the gods like.
5. [The Devil's Fruit in the American Manga: The main character only wants to eat all the Devil's Fruit in the American Manga world. There is no enemy that the Devil's Fruit cannot defeat!]
The above novels are full of fantasy, and the demon fruit is an important element. I hope you will like my recommendation.
The Fire Devil Fruit could make Naruto more confident. Having such a powerful ability would give him an edge in battles and make him feel more capable. This newfound confidence could also change how he interacts with his friends and allies. He might be more assertive in leading them.
I recommend the two novels, One Piece: I'm a Big Boss and Naruto: The Demon's Law, to you. The main character of One Piece I Am a Big Boss became the West Ocean mafia in the world of One Piece. He ate the fruit of the Demon's Eye and became the world's big boss. Meanwhile, the main character of Naruto Demon Law, Medicine Master Yu, awakened the Demon Fruit in Naruto World, and the human puppets he created also had the ability of the Demon Fruit. I hope you like my recommendation.
If Naruto had the Fire Devil Fruit, his combat style would change drastically. He could combine his existing ninja skills with the power of the fruit. For example, he might be able to infuse his Rasengan with fire, making it even more powerful. Also, his mobility could be enhanced as he could use fire to propel himself in new ways. This would make him a more formidable opponent in battles against strong foes like Sasuke or Pain.