Space Marines can also be main characters. They might be tasked with protecting an STC site or escorting Tech - Priests to retrieve an STC. Their combat skills are crucial in fending off threats.
One interesting story could be about the rediscovery of an STC in a long - lost sector. It might involve a group of Tech - Priests on a quest to retrieve it and face various xenos threats along the way.
The Space Marines are very common main characters. They are genetically enhanced super - soldiers, and their stories often revolve around their missions to protect the Imperium.
Often, there are tech - priests among the main characters. They are crucial as they can understand and potentially repair ancient technology. Their knowledge is both a blessing and a curse as it makes them targets.
Often, you'll find the precursor scientists and engineers who were at the forefront of the technological advancements. They were the ones creating the STC systems and exploring the boundaries of science. Another type of main character could be the early leaders of humanity, those who were trying to guide the species during this age of growth and expansion.
The Space Marines are often included. Their strength and honor make them appealing protagonists in a harem scenario. For example, a Ultramarines chapter member could be the center of a harem with female characters being drawn to his noble deeds.
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.
In this type of fanfiction, the main characters associated with the 11th Primarch can vary widely. There could be Inquisitors who are either investigating the 11th Primarch or working with him. These Inquisitors could bring their own motives and agendas. Tech - Priests might also be important characters as they could be interested in any new technology or knowledge that the 11th Primarch might possess. And of course, there could be Chaos Lords who see the 11th Primarch as a threat or an opportunity for their own dark purposes.
The Emperor is also a common character. Fans like to imagine how his actions in different time periods could change the fate of the galaxy. His vast power and knowledge make for great time - travel - related storylines.
One of the main characters is Ciaphas Cain. He is from the 'Gaunt's Ghosts' series. He is a bit of a reluctant hero, always getting into and out of trouble in the most interesting ways.
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.