They can be blended by creating crossovers in the plot. For instance, the Shirai Ryu's weapons and fighting styles can be incorporated into the wizarding battles in Harry Potter. A wizard could use a Shirai Ryu sword enchanted with magic.
Another way is through character interactions. A Shirai Ryu ninja could befriend Harry Potter and they exchange knowledge. The ninja could teach Harry about their code of honor while Harry teaches about magic spells. This would create a really interesting dynamic in the fanfiction.
One interesting 'Harry Potter Shirai Ryu' fanfiction could be one where the magical world of Harry Potter intersects with the ninja skills of Shirai Ryu. Maybe a story where Harry discovers an ancient Shirai Ryu scroll in Hogwarts library and starts to learn their techniques, using them to fight against Voldemort in a unique way.
Another way is through character development. A character in Harry Potter, say Neville, could go on a journey to master a bankai - like power. This could involve him training in a special place, like the Room of Requirement, which could transform into a training ground similar to the ones in 'Bleach' for bankai training. He would face challenges and grow as a character, all while blending the two concepts.
Naruto himself is often a popular character in such fanfiction. Writers might explore how he would adapt to the Shirai Ryu techniques and incorporate them into his already vast array of skills.
Character crossovers are essential. If a Red Lantern like Atrocitus were to enter the Potterverse, he could bring his unique view on justice and vengeance. This could contrast with Harry's more morally - complex view of fighting evil. Their interactions could drive a great story, as Harry tries to understand this new, more extreme way of dealing with wrongdoings.
One interesting Naruto Shirai Ryu fanfiction could be about a young ninja who discovers a hidden Shirai Ryu technique that was lost for centuries. This discovery sets him on a journey to master it and use it to protect his village from a new and powerful threat.
One way is through character creation. For example, a new character could be based on a Norse god or goddess, with their powers and personalities reflected in the Harry Potter world. So, like a character inspired by Thor could have the power of lightning in the magical context of Hogwarts.
The worlds can be blended by having Barbie visit Diagon Alley. She could be amazed by all the magical items and use her fashion sense to customize her wizarding robes. For instance, adding some sparkly elements that are typical of Barbie's style.
The blend can occur through the use of magic in relation to trigonometry in solving problems. For example, in a fanfiction, a magical creature is lost in a forest that is magically generated with trigonometric patterns. The characters need to use their knowledge of both magic and trigonometry to find the creature. Also, a character's magical power could be related to their understanding of trigonometry, so as they learn more math, their magic becomes stronger and more versatile.
Well, often in such fanfiction, the magic systems are combined. For example, spells from Harry Potter like 'Expelliarmus' might be used in the Skyrim setting. Writers might have a character who is a wizard from Hogwarts suddenly find themselves in Skyrim and use their magic there. It creates a really interesting crossover where the different rules and powers of each magic world collide.
In some fanfictions, the Industrial Revolution might be incorporated into the Harry Potter world by introducing new magical devices created with industrial - era concepts. For example, there could be magically - powered factories in the wizarding world producing potions or wands on a larger scale. This could change the economy and social structure within the wizarding community, as mass production might lead to different power dynamics among the wizarding families who own these new industries.