Sasuke might be in shock at first. He can't believe that Naruto is dying in his arms. He may feel a great sense of guilt, thinking that he could have done more to prevent it.
Well, Deku's arm loss happened when he faced an adversary whose abilities were beyond what he could handle. It was a high-stakes moment that had a huge impact on the story.
Well, in some versions of this fanfiction, it might be that Naruto uses a powerful and forbidden jutsu to defeat an overwhelming foe. This jutsu drains his life force, and Sasuke, who has just realized how much Naruto means to him, catches Naruto as he collapses. It could also be that Naruto is poisoned, and Sasuke tries his best to save him but fails in the end, and Naruto passes away in his arms.
It could be that she has new interests now. Perhaps she has discovered other characters or storylines in the Naruto universe that are more appealing to her. Or maybe she has become more interested in things outside of the Naruto fanfiction world, like other forms of literature or hobbies.
He could also become more vengeful. If Sakura's death was caused by an enemy, Sasuke would stop at nothing to avenge her. His focus would shift solely to seeking revenge, and his already formidable skills would be honed even further in his quest for retribution.
One emotional moment could be Sasuke's realization of losing Sakura. His usually stoic facade might crumble as he holds her lifeless body, perhaps reminiscing about all their shared moments, from their early days as teammates to the more complex relationship they developed over time.
In the 'naruto is protected by sasuke fanfiction', Sasuke's protection of Naruto could be multi - faceted. Sasuke, being a powerful ninja, would first of all use his physical strength and speed to block attacks aimed at Naruto. Emotionally, his bond with Naruto would make him extremely vigilant. He might sense Naruto's distress from afar and rush to his aid. In terms of strategy, Sasuke would likely plan their movements carefully when they are in dangerous situations, ensuring Naruto is always in a relatively safe position. His ability to quickly analyze a battle situation and react accordingly would be crucial in protecting Naruto.