Early on, the only resource was energy. It refills on its own, and you spend it to summon troops. That's fine, but it makes every match the same shape: wait for the bar, spend the bar, repeat. We wanted a second resource you had to work for.
Two resources
So now there are two. Energy still regenerates on its own and pays for troops. Sustenance has to be gathered off the battlefield, and it pays for spells.
We actually shipped this as "ore" first and immediately hated it — it felt like it belonged in a different game. Renaming it to sustenance fit Uvuland better: you're feeding the kingdom, not mining it.
The farmer is the interesting part
Sustenance is collected by Cheffy, the farmer. He walks out to the nodes scattered around the board, gathers, and carries it back to your base. He doesn't fight at all.
Here's the part we like: a farmer carrying sustenance is a target. If you catch an enemy farmer out in the open and kill him before he gets home, the sustenance he was carrying goes to you. So sending farmers out is a real risk, and going out of your way to hunt the other player's farmers is a real strategy. The economy isn't a number that just goes up in the corner — it's something happening on the board that you can attack.
Why bother farming at all
Because it compounds. The total sustenance you've ever gathered — not what you've spent — slowly raises your base's level. A higher-level base regenerates energy faster and makes your King spell hit harder. So farming early pays off the whole rest of the match, which gives the player who's behind on troops a reason to play for the long game instead.
Spells all cost sustenance: the King fires a burst from your base, Mega Barf temporarily doubles your energy regen, and Rotten Roast bolts a big chunk of HP onto your base.
What's left
The sustenance nodes are still a placeholder sprite — a little blob — and we're still feeling out how many farmers is too many before you've just turned your whole economy into a liability. But the tension we wanted is there: every farmer you send out is a bet.