One could also write a story where a character from Touhou and a character from Undertale meet in a neutral dimension. They form an unlikely friendship and decide to explore each other's worlds together. They would face various challenges in both universes as they are outsiders. In the Touhou world, the Undertale character might be baffled by the strange magic and numerous spirits, while in the Undertale world, the Touhou character has to deal with the morality of the monster - human relationship. This kind of plot can explore the differences and similarities between the two universes through the eyes of the two main characters.
A plot could be that some of the Touhou characters accidentally end up in the Undertale world. They then have to find a way back home while also getting involved in the conflicts between the monsters and humans in Undertale.
Another idea is that a powerful entity from Undertale enters the Touhou universe and starts causing chaos. The Touhou characters must team up to stop this intruder. Along the way, they learn about the unique aspects of the Undertale world.
Perhaps 'Touhou in the Underground: A Crossover Fanfic' would work well. It gives a sense of the Touhou characters being in the Undertale setting.
Another plot could involve a crossover of the two worlds' educational systems. The students from Ansatsu Kyoushitsu might attend classes in the Touhou world, learning magic instead of assassination. And vice versa, some Touhou characters could come to the school to learn about modern - day combat skills and strategies.
Maybe the Azur Lane ships find themselves in Gensokyo, the world of Touhou. They have to adapt to the strange new environment filled with yokai and magic. The shipgirls could form alliances with the Touhou characters to solve problems that arise from their two different worlds colliding, such as a shortage of resources in Gensokyo due to the sudden arrival of so many outsiders.
In 'touhou crossover fanfiction', adaptation is a big theme. The Touhou characters need to adapt to the new environments of the crossover universes. Whether it's a high - tech sci - fi world or a medieval fantasy land, they have to learn new skills or use their existing ones in different ways. Additionally, mystery is often present as the characters try to figure out the secrets of the new world they've entered.
Well, in Touhou Project crossover fanfiction, a cool concept is the combination of Touhou with modern-day settings like a big city. Imagine Marisa Kirisame flying her broomstick over skyscrapers. Also, crossovers with other video game worlds are great. For instance, Touhou characters in the world of Super Mario, where they might have to deal with Mario - style obstacles. It's all about mixing the familiar Touhou elements with something new and unexpected.
Another theme is cultural exchange. The RWBY world has its own set of values, cultures, and technologies, and Touhou has its own very distinct world of youkai and magic. Fanfictions often show how the characters from each world learn about and adapt to the other's culture. For example, a RWBY character might be fascinated by the way magic is used in Touhou. It can be really interesting to see how they incorporate elements of each other's worlds into their own understanding. And this can also lead to some character growth as they expand their perspectives.
One popular 'touhou crossover fanfiction' is the one that crosses over with 'Pokemon'. It's really cool to see the characters from Touhou in the Pokemon world, with unique storylines like Reimu becoming a Pokemon trainer. Another great one is the crossover with 'Final Fantasy'. The magic systems of both get intertwined in interesting ways.
Well, there's a 'touhou crossover fanfic' that involves the world of 'Overwatch'. In this fic, the Touhou girls get involved in the battles and team - based action of Overwatch. It's really interesting to see how their abilities from the Touhou world translate into the Overwatch setting. Then there are those crossovers with 'My Hero Academia', where the Touhou characters might have quirks or interact with the heroes and villains in that universe.
The unique elements also include the mixing of the two different types of enemies. You have the grotesque and often very large enemies from Dark Souls like the demons and dragons, and then you have the more fantastical and sometimes cute enemies from Touhou. In the crossover fanfiction, seeing how the characters from each side deal with the other side's enemies is really engaging. For example, a Dark Souls knight trying to figure out how to fight a mischievous youkai from Touhou. And the way the stories play with the concepts of souls in Dark Souls and the spiritual energy in Touhou is also quite special.
Well, in such crossovers, a cool concept is the combination of Yu - Gi - Oh's summoning mechanics with Touhou's character traits. Imagine if Marisa could use her thieving nature to steal opponents' summoned monsters in a Yu - Gi - Oh - like way. Also, the setting of Gensokyo in Touhou could be integrated into Yu - Gi - Oh's multiverse concept. This might lead to duels taking place in Gensokyo's unique locations, with different rules based on the local magic and spirits there.