Physically, Naruto can use his Rasengan or other powerful jutsus to fend off enemies attacking Boruto. His combat skills are top - notch, and he won't hesitate to engage in battle to keep Boruto safe.
Well, it could be really interesting. Naruto might have Wesker's sleek, black outfit and his sunglasses. His hair could be styled differently to resemble Wesker's more groomed look. In terms of personality, Naruto might lose some of his naivete and become more like Wesker - cold, calculating, and focused on a single goal. Maybe in the story, Naruto is part of some strange experiment that gives him Wesker - like features and he has to deal with the consequences, like being shunned by his village or trying to find a way to reverse the changes while still using his new - found powers for good.
In the 'boruto kills naruto fanfiction', a motive could be a power struggle. Boruto might believe that Naruto's power is holding back the village's growth or his own potential. He could think that by eliminating Naruto, he can bring about a new era of power in the Hidden Leaf. Also, it could be out of desperation. If Boruto is in a situation where he believes that killing Naruto is the only way to save someone he loves, like his mother or a friend, he might take such a drastic step.
Maybe it's the high expectations that Naruto has for Boruto. Naruto is a hero, and he might unknowingly put a lot of pressure on Boruto to follow in his footsteps. Boruto could be scared of not being able to meet those expectations.
They could start by having an honest conversation. Naruto could sit down with Boruto and just listen to his fears without judgment. This would be a first step in building a better relationship.
Sasuke is very likely to be involved. He has a close relationship with Naruto and is also an important figure in Boruto's life. His skills and knowledge could be crucial in any adventure or situation that Naruto and Boruto find themselves in. Another character could be Hinata. As Naruto's wife, she would surely be concerned about any strange events involving Naruto. And for Boruto, she is his mother, so she would play a role in any family - related or village - threatening situations.
One possible reason could be in the realm of artistic interpretation in the fanfiction. The author might want to explore a different aesthetic or a unique plot where Naruto has some physical or behavioral traits similar to Orochimaru for shock value or to create a new kind of character dynamic.
Boruto's reaction would be complex. He'd be heartbroken, for sure. He might start to question his own worth and purpose. But over time, he'd realize that he has to carry on Naruto's legacy. He'd become more serious and focused. He'd also become more empathetic towards others, understanding the weight of sacrifice. He might even start to study Naruto's techniques and leadership style more closely, trying to emulate the things that made Naruto such a great Hokage and hero.