The Undead treasure these dull green flasks.
Fill with Estus at bonfire. Fills HP.
Everyone’s lifesaver, the Estus Flask. Wanting to know what Estus was exactly, I looked it up. Searching ‘estus’ brings up mostly Dark Souls results but doesn’t explain anything. So on a whim, I decided to throw the word ‘Latin’ in the search box too, because many fantasy terms and names are derived from Latin.
Sure enough… estus means heat.
This is a suggestion that when you refill your estus flasks, you really are refilling them with the essence of the bonfire itself. Most of us probably assumed something similar, but let’s think about that for a moment. The bonfires in Dark Souls are not just fires. They don’t burn on charcoal or wood, but on humanity. So you’re essentially taking a little bit of that humanity with you in a small container, to refill your health and keep you human (alive).
It all seems pretty obvious when you stop and think about it, but I think it’s neat nonetheless, because not all games put that much effort into what’s normally just a game mechanic. They could have easily just said, here’s the generic healing item, since it’s a given and nobody would have questioned it. But in Dark Souls it seems everything has meaning behind it, even if it’s vague.