One possible scenario could be that Natsu is killed in a battle against a powerful and unexpected enemy. Maybe a new dark mage appears with powers that can overpower Natsu's fire magic.
Another scenario might be that Natsu sacrifices himself to save his friends or his guild. He might put himself in the line of fire, knowing that his death would ensure the safety of those he cares about, like using his last bit of strength to hold off a huge magical explosion.
Perhaps in the fanfiction, Natsu is betrayed by someone he trusts, which leads to his death. It could be a friend who has been secretly working for an evil force and stabs Natsu in the back, literally or figuratively.
One possible scenario could be that Natsu confesses his love to a character, perhaps Lucy, and she rejects him because she doesn't see him in that way. She might think of him only as a good friend. Another scenario could be that Natsu is rejected in a job or a quest application within the fanfiction world. Maybe the guild he wants to join or the person in charge of a certain task doesn't believe he has the skills or the right attitude.
One possible scenario could be that he is killed in a lightsaber duel by a powerful Sith opponent. Maybe this new Sith has some secret technique that Anakin couldn't counter.
In such a fanfiction, one possible scenario could be that Gladion gets involved in a battle against a powerful and malicious Pokemon trainer. The trainer's Pokemon might use a super - powerful attack that Gladion's Pokemon can't withstand, and in an attempt to protect his Pokemon, Gladion gets caught in the crossfire and is killed. Another scenario could be that he stumbles upon a dangerous, secret organization within the Pokemon world that doesn't want their secrets exposed. They might target Gladion and assassinate him to keep him silent.
One possible scenario could be a power imbalance. Maybe Sasuke discovers some new, extremely powerful jutsu that Naruto has no defense against. For example, a jutsu that can nullify Naruto's chakra or attack his spirit directly. Another possibility is a miscommunication or a breakdown in their relationship. If Sasuke believes Naruto has betrayed him in some way, his anger could lead him to kill Naruto. However, this goes against the core of their bond in the original series.
Well, in a fanfiction, he might be killed by his own hubris. Let's say he continuously underestimates the power of human ingenuity. A group of scientists manage to create a device that disrupts his energy source. While he's weakened, the military launches a full - scale attack using advanced weaponry specifically designed to target his unique physiology. So, his overconfidence in his invincibility leads to his downfall.
Perhaps in the fanfiction, Natsu is betrayed by someone he trusts in a mission. For example, they might leave him behind in a dangerous situation to fend for himself while they take the credit for the mission. Or it could be that a love interest betrays Natsu by choosing someone else over him due to some false perception or external pressure.
Sometimes, it's just a way to shock the audience. Fanfiction authors often like to take risks and do unexpected things to their beloved characters. Torturing Natsu can be a very unexpected and extreme move that can leave a lasting impression on the readers, whether they like it or not.
In 'naruto gets angry fanfiction', one possible scenario could be that Naruto gets angry when he discovers someone has been mistreating his friends in the village. He might immediately confront the wrongdoer with his signature rasengan at the ready.
Maybe he gets mad when his friends are in danger. For example, if Videl is threatened by a powerful villain, Gohan's protective nature kicks in and he gets really mad.
One possible scenario could be Meredith getting hurt during a surgical procedure. Maybe there's a complication, like a sudden bleed or an equipment malfunction. Another could be she gets into an accident outside the hospital, like a car crash on her way home. And it could also be that she gets hurt in an act of self - sacrifice to save a patient or a colleague.