Well, Naruto might gain some unique abilities from the dog contract. For example, he could have enhanced senses like better smell or hearing. Maybe he'd be able to communicate with dogs more effectively and use them in battles in new and creative ways.
In this fanfiction, signing the dog contract could lead to Naruto forming a special bond with a particular dog or a group of dogs. This bond might not only be about combat but also about emotional support. He could learn more about the dog realm and its secrets, which could help him in his overall ninja journey. The dogs could also teach him some unique ninja techniques that are specific to their kind.
The 'Naruto signs the dog contract fanfiction' could be really exciting. When Naruto signs the contract, he might find himself in situations where he has to prove himself to the dog spirits. He could go on quests or missions assigned by the dog contract holders. This could involve rescuing lost dog spirits or protecting a special place in the dog realm. And with the new powers from the contract, he would have to adapt his fighting style, which would make for some really cool battle scenes.