When Batman sacrifices himself in fanfiction, it can also be a way to explore the darker side of Gotham. Maybe his sacrifice was in vain, and the city falls deeper into crime and corruption. Or perhaps it leads to a new kind of hero emerging, inspired by Batman's last act. It could also show how the villains react, some might be glad that their nemesis is gone, while others may feel a strange sense of loss as Batman was always a worthy opponent.
The immediate impact would likely be chaos. Criminals would feel emboldened, thinking that there's no one to stop them. The police force would be under a great deal of stress as they try to fill the void left by Batman. However, Batman's sacrifice could also inspire new heroes to rise up. People who were inspired by his selfless act might take it upon themselves to protect the city in their own ways.
In fanfiction where Batman sacrifices himself, a frequent theme is the power vacuum. With Batman gone, who will control the criminal underworld? Will new heroes or villains rise to power? Another theme is the emotional turmoil of the supporting characters. Alfred, for example, has to deal with the loss of someone he considered like a son. And the theme of hope can also be explored. Does Batman's sacrifice give the people of Gotham a new sense of hope, or does it shatter their faith in heroes?
Well, it could be that Naruto sacrifices himself to seal away a dark and ancient curse that is threatening to destroy not only the ninja world but all of existence. He realizes that his unique connection to the tailed beasts and his strong willpower make him the only one who can perform this self - sacrificing sealing jutsu. So, he says his goodbyes to his friends, family, and the village he loves and gives up his life to save everyone.
It could be a long - lost Uchiha with powers beyond that of Madara. This Uchiha could have been in hiding, gathering power and knowledge, and his ultimate goal is to reshape the world in his own dark image. Naruto realizes that the only way to stop him is by sacrificing himself.
I'm sorry I can't directly recommend a specific 'Percy sacrifices himself for Artemis' fanfic. But you can try searching on fanfic platforms like Archive of Our Own (AO3). There are tons of fanfics there, and by using relevant keywords in the search bar, you might be able to find one that suits your interest.
In the fanfic, it could be that Fleur is in a situation where she has to perform a dangerous task to save the wizarding world, like going into an ancient and deadly magical place. Harry, realizing the importance of her mission and also having deep feelings for her (maybe a secret love), sacrifices his own safety by going with her and ultimately giving his life to ensure she can complete the task and save everyone.
Perhaps in the fanfic, there is a prophecy that states only a hero's ultimate sacrifice can save Artemis from a dark curse. Percy, being the selfless hero he is, decides it has to be him. He goes through a series of trials first, trying to find an alternative way but in the end, he has no choice. He sacrifices his life force to break the curse on Artemis. This act not only frees Artemis but also has far - reaching consequences in the Percy Jackson universe, like changing the power dynamics between the gods and demigods.
One possibility is that Percy sacrifices himself to save his friends and Camp Half - Blood from a powerful, unbeatable enemy like an ancient primordial god. He might use his powers to create a shield or diversion that allows everyone else to escape while he faces certain death.
In fanfiction, Naruto sacrificing himself for Obito could be a very emotional and dramatic concept. It might show Naruto's ultimate selflessness, believing that Obito is worth saving at the cost of his own life. This could be due to Naruto seeing the good in Obito that others might not, like the part of Obito that was once a kind - hearted shinobi.