A mentor figure could be the one betraying the mc. The mc trusted this mentor completely, but the mentor has some hidden motives. Maybe they are working for a greater evil and see the mc as a threat or a tool to be used, so they betray the mc, which then causes the mc to turn dark.
The theme of secrecy is quite prevalent. The MC has its own set of rules and secrets, and when a romance blossoms, these secrets can either bring the couple closer or tear them apart. Another theme is the idea of the outsider. Often, the female lead is an outsider to the MC world, and her entry into this world and relationship with an MC member is a central part of the story. Also, the theme of family, not just in the traditional sense but also the MC as a family, plays a role in the relationships and the overall story.
One interesting 'dark mc fanfiction' could be about the main character facing a series of dark magic curses in the Minecraft world. Maybe they have to battle against an unseen force that is slowly corrupting the land and its creatures.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a wide range of fanfictions, and you can search specifically for 'dark mc fanfiction' using the search bar. There are often filters you can use to sort by popularity or recency.
Sure. 'Blacktop Cowboy' is a great one. It tells the story of a woman who gets involved with a rough and tumble MC, and their relationship is full of angst and passion. There's also 'Outlaw's Obsession' where the hero is a brooding biker and the heroine is drawn into his dark world. 'Rebel Love' is a novel that shows the darker side of MC life and the unexpected romances that can form there.
One possible plot could be that the main character (mc) is betrayed by a close friend or ally. This betrayal shatters their trust and makes them see the world in a different, darker light. They might then start to use more ruthless methods to achieve their goals, perhaps seeking revenge against those who wronged them.
Character development is crucial. Since the 'Out of the Dark' setting is so challenging, it forces the characters to change. They might start as naive recruits and end up as battle - hardened veterans. Their beliefs can be shaken or strengthened. There could be a Guardsman who starts with blind faith in the Emperor but then has to question everything when faced with the true horror and complexity of the Warhammer 40k world in this 'Out of the Dark' scenario.
The novels also focus on the internal struggles within the Imperium. There are power plays, different factions vying for control, and the challenges of maintaining order in a universe filled with chaos. For example, the different Space Marine Chapters may have different views on how to deal with the emerging threats, which causes some tension.
The antagonists from the forces of Chaos are also key in a way. Characters like the Chaos Lords or daemonic entities create the conflict. Their actions and plots drive the story forward as the Imperium has to counter their threats. Their motives of spreading chaos and destruction set the stage for the intense battles and struggles in the novels.