One popular theme could be alternative character relationships. For example, exploring different dynamics between Alucard and other characters in the Hellsing universe. Another might be unique takes on the vampire lore within the Hellsing world, like how vampires interact with humans in new and interesting ways. Also, some fanfictions might focus on the power struggles within the Hellsing Organization from a different perspective.
The unique take on the original Hellsing story. Since it's abridged, it often condenses the plot in a humorous and sometimes unexpected way, which makes for an interesting read.
Fanfiction is generally in a legal gray area. Since it is often based on existing copyrighted works like Hellsing, it depends on various factors. In most cases, as long as it's non - commercial and not causing harm to the original work's marketability, it's tolerated. However, watching it in the sense of someone reading it out loud in a video or something similar without proper authorization could potentially run into legal issues.
You can try some fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions, and you might be able to find the 'hellsing watch hellsing abridged' fanfiction there.
Most fanfiction is created by fans out of love for the original work, like Hellsing abridged fanfiction. Usually, the law is more concerned with preventing plagiarism and unauthorized commercial use. So, if you're just watching it for fun and not participating in any illegal distribution, it's likely legal.
Immortality in Naruto - Hellsing fanfiction can bring a whole new level of storytelling. In Naruto, some characters are effectively immortal through means like the tailed beasts' chakra. In Hellsing, vampires are immortal. Combining these, a story could be about a character trying to find a way to end the immortality curse. Maybe Naruto uses his sage mode to understand the nature of vampiric immortality in Hellsing.
One possible crossover in Naruto and Hellsing fanfiction could be the sharing of powers. For example, Naruto's ability to use chakra could be combined with the vampiric powers in Hellsing. Maybe a character from Naruto gets turned into a vampire and has to deal with the new powers and the moral implications in the Hellsing universe.
He'd bring a new sense of hope. The Hellsing organization is often mired in dark and violent affairs. Naruto's positive attitude could be a breath of fresh air for the members. For example, Seras might be inspired by Naruto's determination to protect those he cares about.
One idea could be that the characters from Highschool DxD end up in the Hellsing universe. Maybe Issei and his friends are mistaken for new types of vampires due to their devil powers. They then have to team up with the Hellsing organization to clear their names and also fight against a common enemy that is threatening both the devil and human worlds in this combined universe.
One great Highschool DxD fanfiction is 'A Devil's Ascent'. It offers a unique take on Issei's character development. For Hellsing, 'The Undead Redemption' is a good one. It delves deeper into the lore of the Hellsing universe. Another interesting cross - over fanfiction that combines both worlds is 'DxD and Hellsing: The Dark Alliance'. It has an engaging plot that keeps you hooked.