Power Source for Argenti Curses

So the ancestral Argenti curses, and their ability to death curse, what’s like… the power source?

Is it a bloodline thing or do they tap into some power akin to the weave/arawyn/pact/etc?

You can choose which source your curse comes from based on the roleplay of your character.

Just to make sure it is clear, power sources do not have any mechanical implications, which is why it is not specified.