Another scenario could be that Gohan contracts a deadly and incurable disease in the fanfiction world. Despite the efforts of his family and friends, including the use of any available advanced technology or magic, he succumbs to the illness, leaving everyone in mourning.
Perhaps Gohan sacrifices himself to save the other Z - fighters. He might choose to take on Cell's full - power attack that was meant for all of them, and in the process, he loses his life. In the fanfiction, it could also be that Cell has some sort of hidden power - up that catches Gohan off - guard and leads to his death.
One possible scenario could be that Luffy sacrifices himself to save his crew during a major battle against an extremely powerful enemy. He might use all his strength and energy to protect them, and in the end, it's too much for his body to handle.
Perhaps in a fanfiction, Gohan dies protecting his family. He stands against a powerful foe that targets his loved ones. He endures a brutal battle, but in the end, his injuries are too severe. His death shatters his family and friends, and the Z - fighters are left to pick up the pieces and continue the fight without him.
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 that Edward sacrifices himself to defeat a powerful and final enemy. He might use up all his alchemy knowledge and power in one last, desperate attempt to save the world, and his body just can't take the strain.
One possible scenario could be that they sacrifice themselves to save the village from an ultimate evil. They might combine their powers in a final, desperate move that exhausts them completely, leading to their deaths.
One possible scenario could be that Tony is in Siberia on a mission gone wrong. Maybe he's facing a powerful enemy there, and despite his best efforts, he gets fatally injured in a fight. Another could be that the harsh Siberian environment plays a role, like he gets caught in a blizzard and succumbs to the extreme cold.
One possible scenario could be that Percy sacrifices himself to save Annabeth from a powerful and deadly monster. Maybe a huge and ancient sea creature that only Percy can hold off long enough for Annabeth to escape, but at the cost of his own life.
Perhaps in the fanfiction, Naruto is betrayed during the battle. By someone he trusted, like a comrade who was secretly working for the enemy. This betrayal catches him off - guard, and he is severely injured. Unable to fully recover, he succumbs to his wounds during the fight.
One possible scenario could be that Tony sacrifices himself to save a teammate during a dangerous mission. Maybe he takes on a bomb - defusing task and runs out of time, dying heroically.