Well, the leveling - up aspect is a key feature. It shows the character's growth from being a parasite. Usually, this would involve a change in status, power, and abilities.
One unique feature is the concept of starting as a parasite. It's not a common starting point for protagonists in light novels. This gives a fresh take on character development.
I haven't read this web novel specifically. But generally, in such 'level - up' type novels, there might be elements like the main character evolving from a weak or parasitic state to a strong and independent one. Maybe there are exciting battles, character growth arcs, and unique power - up systems.
One similar novel could be 'The Weakest Occupation 'Blacksmith,' but Became the Strongest'. It also has a theme of starting from a seemingly weak or unassuming position and leveling up in a unique world.
One could be 'That Time I Got Reincarnated as a Slime'. It has a similar theme of a character starting from a rather weak or unexpected state and growing in power. Another might be 'Overlord', where the protagonist also has an interesting evolution journey in a new world.
I don't know as I haven't read the novel. It could be the character who was a parasite and is on the journey of leveling up, and perhaps there are other characters who help or hinder this process.
I'm not sure specifically as I haven't read this novel in detail. But generally, it might be about a character's growth from a parasitic state, perhaps evolving morally, socially or in terms of abilities.
You can try searching for it on popular web novel platforms like Webnovel, Wattpad, or Royal Road. These platforms host a large number of web novels, so there's a chance you might find 'Parasite Web Novel' there.
I'm not entirely sure as there could be many web novels with the name 'Parasite'. It might be about a story related to parasitic organisms, perhaps in a science - fiction or horror context where these parasites cause strange things to happen to the characters. Maybe it's about a society that has a 'parasitic' relationship, like some people living off others in an unusual way.