The 'legend of darkness' might refer to some ancient or mysterious tale related to the labyrinth. In this fanfiction, it could be that the author is delving into the origin of this darkness, perhaps as a result of a long - forgotten curse or an ancient evil lurking within the labyrinth. The story may then follow the protagonist as they try to either overcome or understand this darkness.
One possible theme is the struggle against the unknown. The darkness in the labyrinth represents the unknown, and the characters have to face their fears to progress.
I'm not sure specifically as I haven't read that particular fanfiction. It could potentially be about a story that involves characters named Darkness and Lily, and perhaps the 'legend 1985' might be related to the setting or some backstory within the fictional world.
There might be a fanfiction that focuses on the backstory of one of the villains in Darkness Legend. Maybe the villain wasn't always evil, but was driven to it by a series of tragic events. It could explore their relationships with other characters before they turned bad, and how their actions now are a result of past traumas. This type of fanfiction can add depth to the overall story and the character.
Lily is surely a main character. She might be a young girl with special abilities or just a normal person thrust into extraordinary circumstances. The Darkness could be represented by a malevolent wizard or a shadowy being. There could also be side characters like Lily's friends or family who play important roles in her journey related to the Darkness. For example, her best friend who tries to protect her from the encroaching Darkness or her wise old grandfather who gives her advice on how to deal with it.
A common theme could be the struggle between light and darkness. Since it has 'darkness' in the name, many fanfictions might explore how the characters deal with the forces of darkness, and how they strive to bring light or balance. Another theme might be friendship or camaraderie, as the characters band together against the challenges presented in the legend.
A popular 'legend darkness' fanfiction is 'Into the Dark Legend'. It's set in a world where legends are real, but a new and menacing darkness is starting to corrupt them. The author does a great job of creating a spooky atmosphere and the plot twists keep you on the edge of your seat.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of various fanfictions, and there's a good chance you'll find some for 'Legend 1985 Darkness' there.
Another theme could be redemption. Maybe Darkness has done some bad things in the past, and through its relationship with Lily, it tries to redeem itself. It makes for a very interesting dynamic.
First, know the source material well. Read and understand the Darkness Legend lore, characters, and settings. Then, come up with a unique idea. It could be a new adventure for the existing characters or a new character's perspective. For example, if there are always heroes in the original, write from the view of a minor villain who has their own reasons for their actions.