In the 'Naruto Saves Luffy and Ace Fanfiction', the main villains might include the World Government from One Piece. They have a lot of power and resources and are often against pirates. Also, there could be some rogue ninjas from Naruto's universe who are attracted by the chaos and want to take advantage of the situation. These villains would pose a great threat to Naruto's mission of saving Luffy and Ace, making the story full of tension and conflict.
Zoro would be deeply affected. He has sworn to follow Luffy and his death would be a huge blow. He might feel like he failed in his duty to protect the captain. He would likely become more withdrawn at first, but then focus on getting stronger to avenge Luffy if there was someone to blame for his death.
A villain like Shigaraki would likely be interested in the power levels in the MCU fanfiction. He's always looking for ways to increase his own power, and seeing the various powerful artifacts and abilities in the MCU might give him some ideas. He could think about how he could use similar things in his own plans to take over the MHA world.
Nami would be inconsolable at first. Luffy has always been there to protect her, and his sudden death would leave a huge void in her life. She would probably cry for days. As time passed, she would remember all the things Luffy taught her about courage and believing in oneself. Nami would start to take on some of Luffy's leadership qualities in a way. She would be more outspoken about her plans for the crew and more determined to see their dreams through. She would also keep Luffy's memory alive by telling stories of his adventures and his selfless acts to new people they meet on their journey.
Nami might be shocked at first. She'd probably look at Luffy with wide eyes, not believing what she just heard. After all, Luffy is not the most romantic or traditional suitor.
She might be initially scared but quickly regain her composure. Uraraka is a brave character. She would likely start looking for ways to escape, using her zero - gravity quirk to her advantage, like floating up to vents or disabling the villains' weapons if she can.
Shigaraki would likely be disgusted if the fanfic made him seem weak or less of a threat. He'd probably scratch at his neck in irritation. Dabi would be dismissive. He'd think fanfics are just a waste of time and not worthy of his attention. Toga, though, might be intrigued. If the fanfic had a lot of blood and gore in it, or if it focused on her relationships in an interesting way, she could be really into it.
They might get angry if the fanfiction shows the heroes in a very positive light and the villains as weak or stupid. They have their pride and don't like to be made fun of or belittled, even in fan - made stories.
They might be shocked. Luffy's Gear 5 is such a powerful and strange form. In the fanfiction, characters could be amazed at his new abilities, like his cartoon - like movements and seemingly limitless power.