It could be a story of rebirth where the protagonist is reborn as a member of a specific race in Warhammer 40k, like an Eldar. They would then have to deal with the internal politics and power struggles within their own race. At the same time, they are aware of the greater threats in the universe such as the Tyranids. Their main plot would be to navigate through the complex web of Eldar society, regain their past memories or powers, and also contribute to the survival of their race against the encroaching darkness of the 40k universe.
The main plot might involve a character being reborn with some sort of special power or knowledge. In the Warhammer 40k fanfiction setting, this could lead to them being hunted by various factions. For example, the Chaos forces might want to corrupt them and use their power for their own evil ends. Meanwhile, the Imperium could be suspicious of this new 'entity' and also try to either control or eliminate them. So, the character's struggle to find their place and use their power for good (or at least their own survival) could be the main plot.
Well, it could be about a character who was once an ordinary person on a peaceful planet. But then, after being reborn in the Warhammer 40k universe, they find themselves in the middle of a battle against the xenos. They might have to quickly learn to use the advanced weaponry of the Imperium and fight alongside the Space Marines to survive. Their main plot could be centered around their journey to become a respected figure in the Imperium while constantly facing threats from all sides.
A Vampire Lord from a long - lost dynasty could be a main character. He might be trying to reclaim his former glory in the 40k universe filled with so many powerful factions.
One possible plot twist could be that the Emperor awakens with a different ideology than expected. Maybe instead of immediately focusing on the destruction of his enemies, he decides to first reform the Imperium from within, causing chaos among the existing power structures.
The story of Warhammer 40k Dark Imperium is centered around the Imperium of Man at a very crucial time. Guilliman, a significant figure, has resurfaced. His return shakes things up as the Imperium has been in a rather dire state. There are the forces of Chaos constantly attacking from all sides. Guilliman tries to bring order back to the Imperium, which has been fragmented over time. The plot also shows how the Imperium's military forces, especially the Space Marines, adapt to the new leadership and the challenges that come with it. It's a story full of battles, political intrigue within the Imperium, and the never - ending fight against Chaos.
The Primarchs could be main characters interacting with her. For example, if she had a vision for the future of the Imperium, she might consult with the more intelligent and far - seeing Primarchs like Guilliman. Another would be the Inquisitors. They are tasked with rooting out heresy and protecting the Imperium, so they could have important meetings with her to report on threats or seek her guidance. And of course, the Custodes. As her personal bodyguards, they would have constant interaction with her in many fanfiction scenarios.
One main theme is the clash of ideologies. Warhammer 40k has its very strict and often dark ideologies, while Star Wars has the light side - dark side of the Force. When combined, it creates a great exploration of conflicting beliefs. Another theme is power. The different types of power in both universes, like the psykers in Warhammer 40k and the Force - users in Star Wars, are compared and contrasted.
The Empress herself is of course a main character. Often, you'll also find Space Marines, as they are a significant part of the Warhammer 40k universe and interact with the Empress in various ways. Imperial Guardsmen may also be present, depending on the plot of the fanfiction.
One idea could be a vampire Space Marine. Maybe a genetic experiment gone wrong in the Imperium that results in a Marine with vampiric traits. He has to struggle with his newfound thirst while still trying to fulfill his duty to the Emperor.
Well, Warhammer 40k lemon fanfiction often contains more focus on relationships and emotions at a more personal level compared to regular fanfiction. It might explore the romantic or sexual aspects of character relationships, which is not always the main focus in regular fanfiction.
One benefit could be sharing of technology. The Eldar have advanced psychic and technological capabilities that humans could learn from. For example, their way of using psychic powers in a more refined and controlled manner compared to the often dangerous and unpredictable human psykers. Humans, on the other hand, have large numbers and a certain tenacity. In a fight against a common enemy like the Necrons, this combined strength could be a great advantage.
Fanfictions about the Lamenters contribute to the overall lore by presenting different interpretations of their abilities and culture. Writers might come up with new ideas about their combat tactics, their religious beliefs, or their relationships with other Space Marine chapters. This diversity of ideas enriches the Warhammer 40k universe as a whole.