Rip teldrassil tree.
The origins of Prana are mentioned in the campaign quests, if you have a spare set of gear and feel like slogging through again with an alt. If not, the Red Basin map description gives a pretty good hint :)
Prana does come up in the campaign quest, first when Orfina presents it to you and proximity to the pyreborn makes it explode. It's still all pretty shallow and hasty. Like a lot of the lore, I hope they flesh it out more. Does the story mention where prana comes from? Will definitely play through and check that out thank you
Oh, I found it! Don't have to bother with another playthrough, just go to your quest log and read through the summaries. Under the "City of the Dead" section they talk about how Prana is literally just condensed chaos energy.
So it seems to occur naturally where chaos gods have died (Red Basin, the mines beneath the dead titan), and/or can be cultivated within and extracted from living things through Creepy Badguy Magic.
That confirms that theory thanks very much. Potentially that means every time we do an invasion, we create prana. Love the term creepy badguy magic. That should be an official thing