One situation could be in battle. Gaara might shield Naruto from incoming attacks, using his sand powers without hesitation. For example, if an enemy ninja throws a powerful jutsu at Naruto, Gaara quickly forms a sand barrier around him to protect him.
In social situations within the fanfiction, Gaara may be overprotective. If other characters start to question Naruto or seem to be a threat to his reputation, Gaara would step in. He might glare at those characters or use his status to silence them, just to keep Naruto from getting hurt emotionally.
Maybe it's because Gaara sees a lot of himself in Naruto. They both had difficult pasts and were kind of loners at first. Gaara wants to protect Naruto from the pain he once endured.
Perhaps in a dangerous environment like an unstable cave or a place filled with wild and aggressive Pokémon. Mewtwo would constantly be on guard around Ash, using its powers to sense any approaching threats and keeping Ash away from potential danger areas. It might even carry Ash to safety if it senses immediate danger.
Well, Naruto could be depicted as being similar to Gaara in their inner strength. Gaara was always strong on the outside but had a fragile heart. Naruto, in this fanfiction, may share that same duality. Maybe he shows Gaara that having a strong will doesn't mean suppressing emotions. He could be the one to show Gaara that it's okay to let others in, since Naruto is always about making friends and bringing out the best in people.
Well, it could change the storyline in many ways. For one, Naruto would have an even stronger support system. Gaara, being overprotective, might prevent Naruto from getting into some of the more dangerous situations he usually jumps into. This could potentially slow down Naruto's growth in terms of combat experience as he'd be shielded from some threats. But on the other hand, it could also give Naruto more emotional stability, which could in turn help him better control his chakra and learn new jutsus faster. Gaara's presence as an overprotective brother could also affect how the other characters interact with Naruto. Some might be more cautious around him because they know Gaara is watching over him like a hawk.
It might start from their first encounter. Naruto's unique ability to see the good in Gaara despite his past as a loner and a feared ninja could be the initial spark. Gaara, not used to such kindness, begins to value Naruto. As they interact more, Gaara realizes Naruto's importance to the ninja world and his own life, so his protectiveness grows.
Sakura might be a bit annoyed at first. She's used to Naruto being independent and always charging forward, and Gaara's overprotectiveness could seem like it's getting in the way. Kakashi, on the other hand, would probably be more understanding. He'd see the value in Naruto having someone looking out for him, but he might also try to encourage Gaara to let Naruto grow on his own a bit. Sasuke could have a very negative reaction. He might see it as Gaara trying to steal Naruto away from him in a sense, especially if he has his own unresolved feelings towards Naruto.
For Naruto, he could develop a deeper understanding of the pain that Gaara has been through. This might make him more empathetic towards others who seem hostile at first. He might also learn new combat techniques from observing Gaara's use of sand in the heat of the Chunin Exams battles.
Naruto would likely show Gaara that the village can be a place of acceptance. He could introduce Gaara to the villagers, starting with the kids. The kids' innocent acceptance of Gaara would be a big step in changing his view. For example, they could play games together in the village square.
Well, in many fanfictions, it might start with Gaara noticing Naruto's unique strength and unwavering spirit. Naruto's ability to reach out to others, even his enemies, could be very appealing to Gaara. Maybe during a joint mission, they have to rely on each other, and Gaara starts to see Naruto in a different light, gradually developing deeper feelings as they spend more time together.
One reason could be that he has deep feelings for her. He might not be used to having such strong emotions for someone and this possessiveness is his way of showing how much he cares.