In a Warhammer 40k horror story, there might be a tale of a small Imperial outpost. They receive a distress signal from a seemingly abandoned ship. When they board it, they find strange, mutated creatures lurking in the shadows. As they try to fight their way out, they realize the ship is a trap, and more and more of these abominations keep coming. It's a fight for survival against an unknown and terrifying enemy.
One funny Warhammer 40k story is about an Ork Mekboy who tried to 'improve' a Dreadnought. He ended up adding so many random parts that the Dreadnought looked like a walking junkyard. It was hilarious when it tried to move and parts kept falling off during battle.
An Ork named Grotbag once challenged a much bigger Ork to a fight for leadership of their small mob. Grotbag was tiny but full of spunk. He started the fight by throwing a squig at the big Ork. The squig latched onto the big Ork's face and started biting. While the big Ork was distracted trying to get the squig off, Grotbag jumped on his back and hit him over the head with a stick until the big Ork conceded. The other Orks found this hilarious and Grotbag became their new leader.
In some of these stories, there are tales of soldiers facing the terrifying Tyranids. For example, a group of Only War soldiers might find themselves in a jungle planet, outnumbered by the swarming Tyranids. They have to use their wits, the terrain, and their military training to survive. They might set up traps, use guerrilla - style tactics, and rely on each other's skills. Each soldier has a role, like the sharpshooter taking out the larger bio - forms from a distance, while the melee specialists deal with the ones that get too close. It's a harrowing and intense battle for survival in the unforgiving Warhammer 40k universe.
'Genestealer' is also quite well - known. It focuses on the terrifying Genestealers and their insidious infiltration. The idea of these alien creatures slowly taking over and the horror they bring to the Imperium makes for a very engaging horror novel in the Warhammer 40k setting.
The idea of chaos corruption is terrifying. A character can start off normal, but as they are exposed to the taint of chaos, they gradually change. Their appearance might distort, and their mind becomes filled with dark thoughts. It can happen slowly and insidiously, like a disease that you can't see until it's too late. For example, a simple Guardsman might start having nightmares, then find himself drawn to strange symbols, and before he knows it, he's a servant of chaos. And this can spread like wildfire in a military unit or a civilian population.
I'm not entirely sure which specific 'Warhammer 40k love can bloom story' you are referring to. There are many different tales in the Warhammer 40k universe. It could potentially be about a relationship that develops between two characters in the grim and dark setting. Maybe it's a story of an Imperial Guardsman and an Eldar finding common ground and a form of love in the midst of all the chaos and war that pervades the 40k universe.
One interesting Warhammer 40k fanfic could be about a Space Marine's journey of redemption. Maybe he made a mistake in a battle that cost many lives, and the fanfic follows his path to make amends. Another could be a story about an Imperial Guard regiment's fight against impossible odds, showing their tenacity and loyalty to the Imperium.
One interesting concept could be the evolution of the factions. For example, how the Space Marines might have developed new combat tactics or even new genetic enhancements. Another could be the exploration of new planets and the strange alien species that might be discovered. Also, the political intrigue within the Imperium could be a fascinating aspect, like the power struggles between different segments of the military or the Adeptus Terra.
One interesting fanfiction could be about a Dreadnought's memories of its past life as a Space Marine. It might explore how it copes with being entombed in the Dreadnought chassis and still having the will to fight for the Emperor.
One interesting Sanguinius fanfiction could be about his early days as a Primarch. It might explore his relationship with the Emperor and how he was trained. Another could be a story where he faces a great enemy that challenges his ideals and strength. And there are also fanfictions that focus on his role in leading his legion and the sacrifices he made for the Imperium.