Perhaps the sword has the power to absorb and redirect chakra. So when an enemy attacks Naruto with a chakra - based jutsu, the sword can absorb that chakra and send it back at the attacker. In the fanfiction, this could make Naruto a very formidable opponent. It also might have some sort of connection to the spirit world, allowing Naruto to communicate with spirits or gain insights from them. This could be useful for him to learn new jutsus or gain knowledge about his enemies.
One possible ability could be enhanced cutting power. It might be able to cut through almost any material, even chakra - based defenses with ease.
Well, in some fanfictions, Naruto might obtain the Sword of Tengu through a quest. Maybe he has to help a spirit or an ancient being in return for the sword.
One idea could be that the Sword of Tengu has a hidden power that only the protagonist can unlock. This power could be related to an ancient jutsu that was sealed within the sword long ago. Another idea is that the sword has a spirit that communicates with the wielder, guiding them in their battles and adventures in the Naruto world.
Naruto himself could be a great main character. Imagine Naruto finding the Sword of Tengu during one of his adventures. He could struggle at first to understand the sword's power, but with his determination, he would eventually master it and use it to protect the village in a new and exciting way.
Maybe the dragon sword has the ability to absorb chakra. When Naruto is in a fight, he could use this to his advantage by draining his opponents' chakra through the sword when it makes contact. This would weaken his enemies and at the same time, the absorbed chakra could be used to power up the sword's other abilities.
The sword could have the ability to cut through any chakra - based attacks. Since Naruto's world is full of ninjas using chakra, this would be a very useful ability. It would allow Naruto to easily defend against and counter his opponents' attacks.
The theme of mystery also runs through 'naruto tengu fanfic'. The tengu itself is often a mysterious creature in these fanfics. Writers use this to create an air of intrigue, like the origin of the tengu, what their true motives are, and how they fit into the existing Naruto lore. This mystery keeps readers hooked as they try to uncover the secrets along with the characters.
The sword might also have a connection to the spirit world. It could allow Naruto to communicate with the spirits of the Uzumaki clan or gain insights from their past. This would give him an edge in battles as he could learn from the experiences of his ancestors.
One possible ability could be enhanced cutting power. It can slice through the toughest of materials, like it's cutting through butter. For example, it could easily cut through solid rock or even chakra - enhanced defenses.
I really like 'Tengu's Aid to Team 7'. In this fanfic, a tengu becomes an ally to Naruto, Sasuke, and Sakura. It has a lot of action scenes where the tengu uses its unique abilities to help the team in their missions. The character development in this fanfic is also quite good. The tengu's presence forces the members of Team 7 to reevaluate their own skills and teamwork. It's a great read for any Naruto fanfic lover.
The sword might be able to enhance Naruto's existing jutsus. For example, his Rasengan could become more powerful when combined with the sword's energy. It could also give him new elemental powers, like the ability to control lightning or fire in a different way than before.