Gold That Works: The Economy
Most of the decisions you make in Castle Arena are money decisions. Since you never steer a soldier, gold is how you play: every building is a bet, and the economy is designed so those bets keep paying, or keep costing, for the whole match.
Income, every seven seconds
Every 7 seconds both players get paid. The castle always gives 14 gold, and on top of that every building adds a share of what it cost: 2% for troop buildings, 1.8% for siege, 1.2% or 0.9% for specials and only 0.4% for towers. Items add nothing. Upgrades count too.
That income is permanent. If a building is destroyed, the income it generated stays with you. A building is an investment in your economy as much as in your army, and losing it on the battlefield doesn't take back the money you already put in.
You start with 300 gold. Bounties add more: each enemy troop you kill pays a little, and a destroyed building pays 20% of what its owner invested.
The progressive tax
Income is taxed in brackets of 25. The first 25 is untouched, and each bracket after that is taxed 10% more than the one before, up to 80%. In practice, a gross income of 30 nets 29.5, 100 nets 85, and 260 nets 142.
Why tax at all? Because otherwise whoever pulls ahead in economy simply keeps pulling ahead. The tax squeezes that gap: between two players who invest everything, income ends up very close. That moves the weight of the match back to what you build, not just how much.
It has a side effect we won't hide: when good economies converge, "higher income" becomes a weak way to break a tie at the time limit. We dig into that in the balance lab post.
Idle gold is a mistake
A troop building pays 2% of its cost every cycle, forever, and trains troops on top of that. Gold sitting in your pocket does neither. We measured it while building the training: with 1,000 gold against an enemy that was already producing, investing in troop buildings won 6 test matches out of 6. Saving won 1 of 6. Opening with War Drums or with two towers lost every time. The Drums (650 gold, +33% damage for all your troops) aren't a bad item; buying them at minute one is the classic beginner trap.
Lumber and legendary crystals
Troop buildings refund their cost as lumber (siege buildings refund 75%). Lumber is the second currency: it pays for specials, towers and legendaries. So the more army you build, the more you can afford in defenses and big plays.
Legendary crystals are the scarce one. You start with one, every legendary building uses one, and the shop sells more for 1,750 gold. If the legendary falls, its crystal comes back.
The shop and perks
The shop keeps a stock per team that refills over time. It sells permanent auras (War Drums, Marching Pipes), scrolls, the Thunder Orb, staves, the Repair Rune, a Mercenary Catapult and the two big hammers: Fury (+100% damage for 30 seconds, unlocked at 5 minutes) and Quad Fury (+300%, unlocked at 10). Items give power, never income. That is the trade.
Before the match you also pick one perk out of three drawn at random, each with a bonus and a drawback. Glass Cannon gives up to +50% damage as your troops lose HP, but costs 10% max HP. Overdrive gives +30% attack speed while it is on, and your income shrinks for as long as you keep it on.
Waves and the Rescue
Each building has its own cycle, but you can sync a building to another one with an equal or longer timer so their troops leave together, as a wave. Honestly, under the current rules syncing matters less than we expected, since troops already bunch up on the lanes.
And then there is the Rescue. You get one per match, and it kills every enemy troop in a large area. On a big wave at your gates it can be worth ten kills; thrown away early, maybe two. If it hits nothing, it comes back after 3 minutes. At the time limit, the side with more Rescues saved wins, which is why the Rescue doubles as a tiebreaker: whoever already spent their emergency button is usually the one about to fall.
— The Castle Arena team