Well, the allure lies in the unique combination of two very powerful and distinct identities. The Dragonborn is already a sort of chosen one with great power, and adding the vampire element just amps up the cool factor. It can create stories full of moral dilemmas, like whether to embrace the vampiric side for more power or resist it to stay 'good'.
One great fanfiction idea could be the Dragonborn Vampire Lord's struggle to maintain his humanity while dealing with the thirst for blood. He might have to make tough choices between using his vampiric powers for good or succumbing to the dark desires that come with being a Vampire Lord.
One great fanfiction idea could be a Vampire Dragonborn who struggles to control their bloodlust while on a quest to save Skyrim. They might face unique challenges as both a vampire and a Dragonborn, like being shunned by some townsfolk but still having to use their dragon powers to defeat powerful foes.
A plot could center around the Dragonborn Vampire Lord's search for a cure. He might hear rumors of a powerful artifact or a wise mage who can reverse his vampirism. Along the way, he meets other vampires who either try to persuade him to embrace his new life or are jealous of his power. He also has to deal with the normal threats in Skyrim like dragons and bandits while trying to keep his vampiric nature a secret from those who would hunt him.
One common theme is the struggle between vampiric nature and humanity. The OC vampire assassin often has to deal with their bloodlust and how it affects their actions and relationships. Another theme is the use of stealth and assassination skills in the Skyrim world. They have to be sneaky to survive and complete their missions.
His Sharingan - if he had it in this godlike state - would allow him to see through illusions in Skyrim. Many of the mages in Skyrim use illusions to deceive their opponents. Naruto could easily counter that. Also, his chakra control could be used to enhance his weapon handling in Skyrim. He could infuse his chakra into a sword or an axe, making it more powerful and able to cut through tougher enemies.
A common theme is the clash of cultures. Naruto comes from a very different world than Skyrim, and when combined with the harem element, there are often misunderstandings and interesting cultural exchanges. For example, Naruto's ninja code might be different from the values in Skyrim.
I also like 'The Blood - Soaked Assassin of Skyrim'. In this one, the OC vampire assassin has a complex relationship with the different factions in Skyrim. It delves deep into their moral struggles as they kill for survival while also trying to maintain some semblance of humanity. It's a very engaging read.
One idea could be that the male vampire dragonborn struggles with his dual nature. He has the power of the dragonborn but also the thirst for blood as a vampire. For example, he might face a moral dilemma when using his dragon shouts to save a village that is afraid of his vampiric side. Another plot could involve him seeking a cure for his vampirism while still trying to fulfill his destiny as the dragonborn. He could travel to ancient ruins in search of a lost spell or artifact that might reverse his condition.
In fanfiction, the possibilities are endless. Naruto being a pureblood vampire is not unheard of. Fanfiction authors are known for their creativity in bending and reshaping established characters. They might use the idea of Naruto as a pureblood vampire to create a whole new narrative. For example, his ninja skills could be intertwined with vampire abilities, creating a really interesting and unique take on the character. His relationships with other characters from the Naruto series might also be transformed in this new vampire - infused scenario, adding a whole new layer of drama and intrigue.