what copyright? if buys daz assets then can freely use those (that's why it's quite common to see popular assets on many games). only copyright this scammer has is story but that same story is used on many games so no copyright even on that.
also don't think daz checks if assets are bought or pirated.
So what makes this game unique and why do people want it to continue?
Your argument is the same as saying "[Insert popular author's name here] is using letters of the alphabet and everybody can freely use those, so he has no copyright on that."
Somebody once said that every story that can be told has been told. Story tropes used today are as old as literature, not a single story is fully original, every book retells a story that has already been told.
No copyright even on that?
Sorry to burst your bubble, but Gumdrop's story has been sufficiently original that people bought into it and paid money to see, read and play through. That thing alone counts as proof that the story has copyright that Gumdrop has granted and infringing on that is risky.
You could claim fair use, but you're not paraphrasing the story for other purposes, you would be rewriting it for the express purpose of selling it as your own.
As much as I'd love to see this game completed as it was meant to be and as much as I want to see people stick it to Gumdrop, it just can't happen this way.