Though not always the case, I love making titles with multiple meanings.
The Abomination Within Letcham
I named it because, frankly, there are a lot of abominations within Letcham. What exactly could the title be referring to? Could be our leading lady, who is vampiric. Could be the man she finds herself relying on who beats her and treats her like an animal. Could be the church, with all their suspicious actions. Could be [redacted for spoilers]. It's up to the reader, and that is why I named it as such. It covers literally everything.
For my wording in particular, I chose "Abomination" because it felt most horror-y (in the tone I'm going for) than something like "monster", that and "Abomination" felt like it fit the aprox.1800s vibe of the webnovel best.
The Temptation of the Sea and its Monsters
This god awful mouthful of a name is very similar to the above. It can mean a lot of things to different characters within the story. This one I can't dive too deep into without spoilers, though. Most the characters are pirates drawn to the sea for any number of personal reasons, and a lot of characters are seeking merfolk (sea monsters) too for any number of personal reasons. Another vague title I made to let the reader draw their own conclusion.
Though this story is set even before "TAWL" (aprox. 1750) I kept this title lighter because it is simply lighter in tone. TAWL is a grimdark, gothic horror while TTotSaiM (or however you'd shorten it) is a swashbucker with action, fun, light moments, romance, and all that good stuff. A lighter, more webnovel-y title just fit better.