[2021] "Hardcore" blood moons suggestion / request.

As it currently stands, there is no way to create a mod that affects external files not related to the functioning of the game. The only way to accomplish what you say currently would be the honor system.

I'm sure some kind of permadeath option will be in the final release or maybe mid to late beta as it's an oft requested feature- But, likely not before then, and likely not tunable to only take effect on horde night specifically.