In these fics, Sakura often becomes badass through intense training. She realizes that she needs to be stronger to change things in Konoha or to prove herself. For example, she might train under a mysterious master or in isolation, like in 'Sakura's Solitary Training' where she spends months alone in the forest, honing her skills.
In some fanfictions, Snape has badass moments when he outsmarts Voldemort. For example, he manages to mislead Voldemort about the location of a crucial magical artifact. He uses his Occlumency skills to his advantage, hiding his true thoughts and intentions while presenting false information in a very clever way. This not only shows his intelligence but also his courage as he risks his life to deceive the Dark Lord.
A great badass science fiction novel is 'Foundation' by Isaac Asimov. It presents a grand vision of a galactic empire in decline and the attempts to preserve knowledge through the Foundation. 'Starship Troopers' by Robert A. Heinlein is also a classic. It explores themes of military service, citizenship, and the nature of the alien threat. Additionally, 'Altered Carbon' by Richard K. Morgan is a really cool one. It has a world where consciousness can be transferred between bodies, leading to all sorts of noir - like detective stories and exploration of identity in a science - fictional context.
In fanfiction, Percy Jackson is a badass because he combines his natural abilities as a demigod with his growth over the course of the original stories. He has the power of Poseidon, which gives him an edge in combat and in solving problems. He's been through so many challenges and has learned from them. This makes him not only physically strong but also mentally tough. Writers in fanfiction can explore his character further, showing him taking on even greater threats and emerging victorious, which cements his status as a badass.
The story of the 300 Spartans at Thermopylae is very memorable. They knew they were facing a huge Persian army but didn't back down. They fought with such ferocity that they held the pass for days. Another memorable one is the story of the Tuskegee Airmen in World War II. These African - American pilots had to face discrimination at home but still fought bravely in the skies over Europe, shooting down numerous enemy planes and proving their worth as pilots.
One badass war story is about the Battle of Thermopylae. A small force of Spartans led by King Leonidas held off a much larger Persian army. They fought heroically in a narrow pass, and though they were ultimately defeated, their resistance became a symbol of courage and defiance. Their sacrifice bought time for the rest of Greece to prepare for the Persian invasion.
One great 'MLP Badass Twilight' fanfiction is 'Twilight's Ascendance'. It shows Twilight in a more powerful and assertive role, facing challenges that really test her abilities. The story has some really cool magic battles and character development for Twilight.