His Dark Materials is a fantasy series that follows the adventures of Lyra Belacqua in a parallel universe where people's souls exist outside their bodies as animal companions. It involves themes of free will, religion, and the power of knowledge.
Lyra is the protagonist, without a doubt. Her journey is what drives the story forward. Then there are the witches. Serafina Pekkala is a prominent witch who helps Lyra at different times. There's also Dr. Mary Malone, a scientist who gets involved in the strange events. And of course, the angels, like Xaphania, are important characters in the novels' cosmology and plot.
One of the main themes is coming of age. Lyra, the main character, grows from a naive girl into a more self - aware young woman. Another theme is the struggle between good and evil, as seen in the battle against the Magisterium. And there is also the theme of the power of knowledge, with the alethiometer being a symbol of hidden knowledge that Lyra has to learn to read.
They're related but not identical. 'The Golden Compass' kicks off the 'His Dark Materials' universe, but the later parts of the series introduce new elements and plotlines that weren't present in just the first book/movie.
Some fanfictions might focus on a particular character from X Men in the His Dark Materials universe. Say, Rogue. She could have a really unique experience in that world. Since she has the power to absorb others' powers and memories, how would that work with the concept of daemons? It could be a really fascinating exploration.
Character development is key. If you're bringing together characters from both, make sure they stay true to their original personalities while also evolving in this new, combined setting. For instance, if Wolverine were to meet Lyra, how would their personalities clash or complement each other? Also, create a engaging plot. Maybe it could be about a threat that only the combined forces of X - Men and characters from His Dark Materials can face.