Roaring Heroes Battle the Overlord (Ainz)

It borrows the world and characters from the anime "Overlord," but the plot is entirely original.
So, is this a fanfiction? I'm not sure.
It's a fantasy story of swords and magic.
There are two main characters.
One is a quirky but powerful girl, the other a mature and steady but weak adventurer.
They embark on a journey to defeat the most powerful evil Overlord, Ainz Ooal Gown.
So can they succeed?
Note: There is almost no romance plot.