The 'fish - out - of - water' trope can be great. Like when Spider - Man first arrives in Red Sonja's world. He's used to the modern cityscape of New York and now has to deal with a medieval - like environment full of swords, sorcery, and different social norms.
A possible crossover could involve Spider - Man getting transported to Red Sonja's world. He would have to adapt his powers to a more medieval - style setting. He could use his webs to swing between the ancient buildings and help Red Sonja in her battles against the local tyrants. Red Sonja, in turn, could teach him some of her sword - fighting techniques.
One great Red Sonja fanfiction is 'The Redemption of Sonja'. It has a really interesting plot where Sonja has to face her past mistakes and make amends. The author does a great job of portraying her strong character.
You can start by looking on fanfiction.net. It has a large collection of Red Sonja fanfictions. Just search for 'Red Sonja' in the search bar and you'll get a list of available stories.
Another theme is the power dynamic. Red Sonja is a powerful warrior in her own right, and Naruto has his own set of extraordinary abilities. Fanfictions often play around with how they compare in terms of strength and who takes the lead in different situations. Sometimes it's a friendly competition, other times it's a more serious struggle for dominance.
You can try looking on fanfiction websites like Archive of Our Own (AO3). They have a large collection of fanfictions, and there's a good chance you'll find some for Spiderman and Red Sonja there.
Red Sonja's origin story has her as a fierce warrior. She hails from the Hyborian Age. She was once a normal woman, but after a series of tragic events, she made a pact with a powerful deity. This pact granted her extraordinary strength, speed and combat skills. She then set out on a journey to avenge her family and became known for her red hair and scant yet iconic armor.
One of the best Red Sonja stories is 'Red Sonja: Queen of Plagues'. In this story, Sonja shows her tenacity and combat skills as she battles against a deadly plague and the forces behind it. Her character is well - developed, and the story is filled with action - packed scenes.
The 'Red Sonja' novel centers around Red Sonja herself. In the story, she travels across different lands. These lands could be filled with all kinds of creatures, from fearsome beasts to strange magical beings. Red Sonja is constantly in a struggle, whether it's against an oppressive ruler or a dark force that threatens the land. Her character is complex, being both a warrior with a tough exterior but also having her own vulnerabilities and a sense of honor that guides her actions.