Mikale's side would likely be in turmoil. His friends or allies would seek revenge. They would probably start an investigation into what really happened and try to find a way to bring Bella to justice, depending on the rules of the crossover world.
The overall community in the crossover world would be divided. Some might see Bella as a hero for taking out a potential threat (if Mikale was seen as such), while others would condemn her actions as cold - blooded murder. There could be a lot of political and social unrest as a result of this act.
Well, it could be a story where Bella has some dark motive to kill Mikale. Maybe in this crossover, they are from different universes with conflicting interests. For example, if Bella is from a vampire - slayer world and Mikale is a vampire - like being in his own world, she might see him as a threat to her world or loved ones.
She could be in shock. Bella might initially be too stunned to react immediately. After all, she trusted Edward completely, and this event would shatter that trust. She may withdraw from him emotionally, at least for a while, as she tries to process what happened.
Sakura would be frightened but also determined to protect her friends. She might use her medical ninjutsu to try and counter any negative effects the Boogeyman has on people. Shikamaru, being the lazy but smart one, would first analyze the situation. He'd come up with a plan that involved minimal effort but maximum effectiveness, like using traps to catch the Boogeyman.
Ruby would probably be both scared and fascinated. She's always been curious about new things, and Godzilla is definitely something new. But she would also be worried about the destruction it could cause. Weiss might be more cautious and initially see Godzilla as a threat to the order in Remnant. Blake would likely be on guard, observing Godzilla's behavior to see if it's truly hostile or not.
Well, when the Avengers first encounter Sephiroth, they'd be quite surprised. Tony Stark would crack a joke to ease the tension a bit but still be very aware of the danger. Steve Rogers would stand tall and be the first to step forward, showing no fear. Thor would grip his hammer tightly, ready to defend. Bruce Banner would be worried that if Hulk gets involved, it could be a very chaotic battle. The female Avengers like Black Widow and Scarlet Witch would be sizing up Sephiroth, trying to find any chinks in his armor. They'd all be on high alert and start formulating a plan to either defeat or contain this unexpected and very powerful new arrival.
Sakura would be devastated. She has always had deep feelings for Sasuke. She might initially be angry with Naruto, thinking that there could have been another way. But later, she might understand Naruto's difficult decision when she realizes the threat Sasuke posed.
Sasuke would likely be filled with rage. He and Naruto had a complex relationship, and Naruto's death at Sakura's hands would make Sasuke seek revenge or at least demand answers. Kakashi, on the other hand, would be deeply saddened. He was Naruto's teacher and would probably feel a sense of failure.
In a romantic - themed fanfiction, if there's a love interest, that person would be extremely concerned. They might hold Bella's hand, whisper soothing words, and even sacrifice their own needs to make sure she gets better. Meanwhile, some rival characters might see this as an opportunity to gain an advantage, but most of the good - hearted characters would come together to help Bella through her fever.
Some villagers might be shocked and horrified. Naruto has always been seen as a hero, and this act of killing the council would shatter that image for many. They would fear that Naruto has gone rogue and might pose a threat to them.
Some fans would be really shocked and sad. Kakashi is a very popular character, and his death at the hands of Obito would be a huge blow to many. They might feel angry towards the author for creating such a tragic scenario.