One story would be 'Star Wars'. The Rebel Alliance stands up against the evil Galactic Empire and eventually emerges victorious. It shows how hope and determination can lead to the defeat of evil.
One common theme is the power of courage. In many good defeats evil stories, the heroes have to be brave enough to face the terrifying evil forces. For example, in 'Alice in Wonderland', Alice shows courage in the face of the Queen of Hearts' tyranny. Another theme is friendship. In 'The Chronicles of Narnia', the friendship between the Pevensie children helps them fight against the White Witch, the symbol of evil.
One example is the story of 'The Lord of the Rings'. Frodo and his companions represent good. They fight against the evil Sauron and his forces. Frodo's journey to destroy the One Ring is a crucial part of good's victory over evil. Another is 'Harry Potter'. Harry, Hermione, and Ron are the good forces fighting against Voldemort, the ultimate evil. Their courage and friendship help them defeat Voldemort in the end.
There's a classic tale called 'The Prince and the Dark Wizard' where the prince's kindness and bravery help him overcome the evil wizard's schemes.
Maybe the 'evil' Dumbledore was a future version of himself who had been corrupted by time - travel gone wrong. Harry, not fully understanding the situation, battles and defeats this future Dumbledore. This could then lead to a complex time - paradox plot where Harry has to find a way to fix the timeline and save the real Dumbledore from this fate.
One great 'harry defeats voldemort fanfiction' is 'The Final Battle Reimagined'. It details an alternate version of the final duel where Harry uses some unique spells he learned from an ancient book. Another is 'A Different Ending' which focuses on how Harry's relationships with his friends play a crucial role in his victory over Voldemort. There's also 'The Hidden Power' where Harry discovers a hidden power within himself that gives him the edge in defeating Voldemort.
One example could be 'The Lord of the Rings' where the forces of good ultimately defeat the evil Sauron.
There could be a fanfiction where Percy teams up with his friends in an unexpected way to defeat Gaia. Instead of the usual battle formation, they all combine their powers in a single, super - powerful attack. Percy leads the charge, using his connection to the ocean to draw in massive amounts of power, while his friends add their own elements like fire, air, and earth (from Annabeth's strategic mind which is like an earth - like stability) to create a blast that overcomes Gaia.
In some fanfiction concepts, Harry might defeat an 'evil' Dumbledore if Dumbledore was secretly under the influence of a dark magic artifact. This could twist his good intentions and lead him to actions that Harry would oppose. Harry, with his strong sense of justice and loyalty, would then fight against this corrupted Dumbledore.
The story of 'Snow White' is a classic good and evil story. The evil queen is jealous of Snow White's beauty and tries to harm her multiple times. Snow White, on the other hand, is kind - hearted. Her goodness is what attracts the dwarfs to help her and also what leads to her final rescue by the prince. Also, in 'The Little Red Riding Hood', the wolf is the 'evil' character who wants to deceive and eat the little girl, while the girl and the hunter are 'good' as they fight against the wolf.
One reason could be that the sister is more dedicated in certain areas. For example, if it's about schoolwork, she might study harder. So when she gets better grades and shows it to her brother, she defeats him. And she might shame him by saying something like 'I study while you just play games'.