One idea could be to have the characters from Kingdom Hearts end up in the world of Nier Automata. Sora could be exploring the post - apocalyptic landscapes, and his keyblade might react in strange ways to the technology and magic present in Nier's world. He could team up with 2B and 9S to fight against the common threats like the machines. The Heartless could also be introduced into Nier's world, creating new challenges for both the heroes of Kingdom Hearts and Nier Automata.
The exploration of technology and its impact on society is another common element. When crossed with a cyberpunk - themed work like 'Cyberpunk 2077', both the advanced robotics of nier automata and the high - tech but gritty world of Cyberpunk 2077 can be used to discuss how technology can both enhance and destroy humanity. This could be through the eyes of the nier automata characters as they experience the new world.
In short, NieR: Automata is a highly-acclaimed game that offers a unique gameplay experience and a thought-provoking narrative. It takes place in a world where machines and androids are at war, and players explore themes of identity, consciousness, and the meaning of existence.
First, you need to do your research on both universes. Know the lore, the characters, and the settings of Kingdom Hearts and Nier Automata. This will help you create a believable crossover. Then, think of a central plot. It could be something as simple as a shared enemy or a more complex idea like the merging of the two worlds' magic systems. For example, how would the Heartless interact with the machines in Nier Automata? Once you have the plot, start introducing the characters. Decide how they will meet and what their initial reactions will be.
There are nier automata crossover fanfics that cross it with 'Ghost in the Shell'. In these fanfics, the themes of humanity and what it means to be alive, which are prominent in nier automata, are explored further in the context of Ghost in the Shell's cybernetic world. The fanfic might have 2B or 9S interacting with the characters from Ghost in the Shell, leading to some thought - provoking scenarios.
NieR: Automata's story draws from multiple sources. It takes cues from classic sci-fi works and explores profound questions about existence and identity. The story is rich and multilayered, making it a standout in the gaming world.