To develop Guitar Villain more, you could explore his backstory. For example, why did he turn to villainy? Maybe he was a struggling musician who was constantly rejected, and Hawkmoth took advantage of his bitterness. This could add depth to his character.
One plot idea could be that Guitar Villain discovers a new power in his music that allows him to create illusions of his greatest desires. He uses this to try and take over Paris, but Ladybug and Chat Noir figure out that they can disrupt the illusions by playing a counter - melody. Another could be that Guitar Villain teams up with a new villain who has the power to enhance his music's destructive capabilities. Ladybug and Chat Noir then have to find a way to split them up and defeat them separately.
The term 'no guitar blues' is rather ambiguous. It could potentially refer to a personal experience where someone has a longing for the guitar but is unable to play it for various reasons. It might be that they don't have access to a guitar, or perhaps they have some physical or mental hindrance that stops them from playing. The full story could involve the person's journey through this difficult situation, how they deal with the absence of the guitar in their life, and how they still manage to experience or express the blues in some way.
Title: 'The Rise of the Shadow Serpent'. In this fanfic, my villain OC is the Shadow Serpent. She was once a kind-hearted girl, but after being betrayed by those she trusted, she turned to the dark side. She uses her power to create illusions and chaos in Paris. Ladybug and Chat Noir face a tough battle as they try to figure out her motives and weaknesses.
To create a great villain for Miraculous Ladybug fanfiction, focus on their flaws and strengths. Make their actions unpredictable and have them interact with the main characters in interesting ways. Maybe they have a hidden agenda or a secret that's revealed later on.
The 'no guitar blues' might be about a blues musician who lost their guitar, perhaps in a tragic accident or it was stolen. This led to a series of events where they had to rediscover their love for the blues without their main instrument. They might have started exploring other aspects of blues like vocal techniques more deeply, or collaborating with other musicians who had guitars. It could also be a story of how they overcame the sense of loss and found new ways to create the bluesy sound they loved.
A villain that has the power to steal emotions could be a great choice. Imagine this villain targeting Edendaphne's friends and allies, draining their positive emotions. Edendaphne would have to find a way to not only stop the villain but also restore the emotions of those affected. It would be a very emotional and intense story.
A new character could be introduced as the main villain. Maybe a corrupt police officer who turns to the dark side. He could use his knowledge of the law and the city's security systems to commit crimes and frame the Miraculous heroes. He would be a formidable opponent as he has insider knowledge.
An evil alien warlord could be the main villain. This warlord could be bent on conquering Earth and other planets in the universe. He might see the Miraculouses as a threat and try to destroy Ladybug and Chat Noir first.
Hawkmoth is an obvious choice. His whole mission is to obtain the Miraculouses, and in a death fanfiction, he could succeed in a more devious way than in the original series, directly or indirectly causing Ladybug's death.