@rotationplus
It shouldn't be hard to write nowadays with enough reading experience and decent writing skills based on WN (LN might quality requires ridiculous amount of plot planning, prose and such).
Write out the character name, write out their personality, checkout the plot point, see how the original ending got axed.
Then simply continue writing.
If you're not used to write fanfic alternatively use AI but do try to imitate the author dialogues with your own text otherwise they break immersion easily lol.