No and yes… A business entity that is proactively protected from liability could not exist without government charter. However, a business entity could employ its own paramilitary and/or hire mercenaries and effectively make itself immune to liability, which works out to the same thing pretty much. And I’m reasonably certain that that’s the future - that corporations will continue to acknowledge and submit to governments only as long as it’s to their advantage to do so, and that when the costs outstrip the benefits, they’ll simply stop, and instead manage their properties as essentially states unto themselves. And at that point, whether or not they have an official declaration of their corporate identity will be irrelevant.

Could the paramilitary unit fund itself without legal tender laws from a state and government created fiat currency?

Sure. They could even do it today simply by paying in Bitcoin. I expect though that the future will see private currencies backed by the-entities-formerly-known-as-corporations. Governments don’t monopolize currencies because nobody else wants to issue one, but because it’s in their interests to monopolize them, and they have sufficient power (for the time being) to enforce their monopolies.