While I'm obviously a bit sad the Leviathan won't be completed, as an author I'm glad you moved away from something you just weren't feeling the inspiration for anymore. What you have now is still a great fic, no matter the completion status (as evidenced by the masses of derivative works. Seriously, I saw animated music videos for Leviathan. Wow).
Side note, my first fanfictions were much worse than Leviathan, though they shared the same quality of having absolutely no long-term plan.
Actually, now that I think about it, Leviathan was one of the fics that got me to start writing for BNHA. Or rather, one of the fics that got me to write eldritch BNHA. Thank you for that, it's been fun and I doubt I would have if not for that inspiration.
Leviathan was and is still one of the fics I regularly come back to, and I thank you for this update.
(Also at some point in the future I may write something inspired by Leviathan if that's alright with you? I've had lots of brainwaves, the most prominent being that Izuku was four. If his quirk was of similar mental age, then of course it lashed out when being held hostage. Basically a "Izuku does not trust his quirk/Leviathan does not understand humans but understands that its host dislikes it/Character study between the two perspectives"- type thing.)
thank you!! and yeah the response to leviathan will never not blow me away. i'm still in awe of it years later
(and i will say technically leviathan was not my first posted fanfiction. that title belongs to a bmc fanfiction that i don't even remember the title of that will never see the light of day again LOL)
and on the eldritch note, i'm glad! i've been told me and daymare got a bunch of people into that, and i'm happy. it was a blast to write, and the more the merrier.
and also yeah go nuts w the writing! i had no problem w derivative/inspired works while leviathan was actively updating; i certainly don't now. best of luck with whatever you create!!