A plot could involve Kirito being cursed by a powerful enemy related to the Seven Deadly Sins' lore. The curse affects his ability to log out or communicate with his own world. In order to break the curse, he has to help the Seven Deadly Sins complete a series of dangerous quests. Along the way, he forms deep bonds with each of the sins and learns about their pasts and how they are dealing with their own 'sins'.
One idea could be an OC who is a hybrid of two of the deadly sins, like pride and envy. This OC could struggle with the internal conflict of these two powerful emotions. For example, being envious of the power of other characters while also being too proud to admit it or ask for help. Another plot could be an OC who is on a quest to redeem the Seven Deadly Sins themselves, believing that they can be reformed. This would involve the OC facing many challenges and having to understand the true nature of each sin.
Another plot could involve fem Naruto being accused of the sin of envy. In the Seven Deadly Sins' setting, she could envy the powers or status of certain characters. She might see how powerful Meliodas is, for instance, and envy his leadership and strength, which could lead to her making some unwise decisions in an attempt to prove herself equal or better.
One interesting plot idea could be that in the Minecraft world, the characters from Seven Deadly Sins are transported there. For example, Meliodas could be on a quest to find a special diamond that has the power to restore his lost strength. And the Minecraft mobs could be influenced by the sins. The zombies could be more aggressive due to wrath, and the pigs could be gluttonous and overeat the crops in the game.
A plot could be that Escanor and Merlin are tasked with training a new generation of knights. They have different teaching styles, with Escanor focusing on physical and mental fortitude, and Merlin on magical abilities. This leads to some humorous and also some tense moments as they try to work together.
A fanfic idea could be to have the Seven Deadly Sins lose their powers and have to learn to rely on their wits and each other in a more human way. This could lead to character development as they face challenges without their supernatural abilities. Also, a story about a new character who is influenced by all the seven sins at once and has to struggle to find their true self in the midst of all that chaos.
Maybe a plot where Merlin discovers a prophecy that only Escanor can fulfill, but it requires him to sacrifice something dear to him. They embark on a journey to find a way around the sacrifice while also falling in love along the way. There could be many challenges like facing ancient guardians and deciphering cryptic riddles.
One idea could be creating an OC (Original Character) who is a descendant of one of the main characters in 'Seven Deadly Sins' and has a unique power related to one of the sins. For example, an OC who is a descendant of Meliodas and has a power that is a variation of his 'Full Counter' ability but is related to the sin of wrath. Another idea is to make an OC that is from a different kingdom entirely and has to deal with the chaos caused by the Seven Deadly Sins. They could start off as an antagonist but later realize the true nature of the sins and join them.
One idea could be creating an OC who is a descendant of one of the Seven Deadly Sins. For example, if your OC is related to Meliodas, they could inherit some of his power but also have their own unique abilities. Another idea is to have an OC who is on a quest to overcome the influence of the Seven Deadly Sins in a world where their presence has corrupted society. They could travel around, facing challenges related to each sin and learning valuable lessons along the way. Also, an OC who is an apprentice to one of the Sins, learning their combat skills and moral code, would be an interesting concept.
One idea could be that the Doom Slayer has to face off against manifestations of the seven deadly sins in the hellish landscapes of Doom. For example, a demon representing Gluttony that constantly consumes everything in its path, and the Doom Slayer has to find a way to stop it from devouring all the resources he needs to survive.
One idea could be a story where Ichigo, with his strong sense of justice, has to confront the manifestations of the Seven Deadly Sins in the Soul Society. For example, he might encounter a Hollow that represents Greed, which is hoarding spiritual energy. He could use his Zanpakuto skills to defeat it and learn something about his own potential for that sin. Another could be a crossover where the characters from Seven Deadly Sins end up in the Bleach universe and Ichigo has to help them find their way back, all while dealing with the chaos they bring. It could be interesting to see how Ichigo's power compares to the abilities of the Seven Deadly Sins characters.