One interesting concept could be the fusion of the Kingdom Hearts' unique magic system with the colorful world of Equestria Girls. For example, keyblades might have new forms inspired by Equestrian elements like ponies or the magic of friendship. Another concept could be the crossovers of characters. Characters from Kingdom Hearts might interact with the Equestria Girls in unexpected ways, leading to new friendships or rivalries. Also, the exploration of different worlds within this fanfiction can be exciting. Worlds could combine features from both franchises, creating a whole new and immersive experience for the readers.
Some interesting concepts include alternate universes where the characters have different roles or relationships. For example, Sora might be a villain instead of a hero. Another concept could be exploring the backstories of minor characters in more depth, like how they came to be in the different worlds.
Sora is often a very popular character. He's the main protagonist in Kingdom Hearts, and when he's brought into the Equestria Girls' world, his heroic nature and his skills with the keyblade make for exciting storylines. Twilight Sparkle is also popular. She's a powerful magic user in the Equestria Girls universe, and her interactions with Sora or other Kingdom Hearts characters can be really interesting. Another popular character is Aqua. Her grace and combat abilities can add a new dimension to the fanfiction when she teams up with the Equestria Girls.
One interesting concept could be a crossover of abilities. For example, Naruto's ninjutsu skills combined with the magic from Equestria Girls. Maybe Naruto could learn to use some pony magic in the fanfiction world, or the Equestria Girls characters could gain some ninja-like speed and stealth.
In Kingdom Hearts Darkness fanfiction, there are often concepts related to the origin of the darkness. Some stories might explore whether the darkness was always there or if it was created by some ancient force. There could also be the idea of a character having to master the darkness instead of simply fighting against it, like using the power of darkness in a controlled way to fight even greater threats in the Kingdom Hearts cosmos.
One interesting concept could be the exploration of the darker sides of the characters. For example, seeing how Sora might struggle with darker impulses or a corrupted Keyblade. Another could be alternate universes where the Heartless have completely overrun the worlds and the heroes have to fight in much more dire circumstances.
One interesting concept could be a new original character (OC) with a unique Keyblade design. For example, an OC whose Keyblade is shaped like a musical instrument, representing their love for music and how it ties into the power of the Keyblade. This could add a fresh dynamic to the battles and interactions in the Kingdom Hearts 3 universe.
One concept could be Naruto and his friends being Keyblade wielders. They could travel between different worlds in the Kingdom Hearts style, using their ninja abilities along with the power of the Keyblade. For instance, Naruto's Rasengan could be combined with a Keyblade attack. Another idea is that the Akatsuki are like the Organization XIII in Kingdom Hearts, with each member having their own unique powers and goals related to both the Naruto world and the Kingdom Hearts concepts of hearts and darkness.
One interesting concept could be exploring the backstory of the Master of Masters in more depth. Maybe his origins, his true motives for his actions in the Kingdom Hearts universe.
Well, in Kingdom Hearts light and darkness fanfiction, the idea of alternate universes where the roles of light and darkness are reversed can be really cool. It makes you see the characters in a whole new light. Also, the concept of a character's inner struggle between light and darkness can be delved into more deeply than in the original games. Fanfiction can show how a character might gradually be consumed by darkness or find new ways to embrace the light.
One interesting concept could be the crossovers with other popular franchises. For example, a crossover with Final Fantasy might bring unique character interactions. The different worlds in Kingdom Hearts already have a diverse range of characters and settings, and when combined with elements from other stories in fanfiction, it can create really engaging scenarios. Maybe a character from Kingdom Hearts visits a world based on a different game or movie, and has to adapt to new rules and cultures.