Arena

• Played on an arena pit — no castles, no build zones, no income. Each round opens a timed buy phase with a budget to spend on units from your faction's buildable list, so your faction pick is your catalog.
• Buys are hidden. Your own picks assemble as a ghost army on your arc of the pit while you shop; everyone else's army is revealed only when the fight starts.
• When the buy timer closes, the armies spawn around the pit and fight to the death on their own — no unit control, and stalled fights are called rather than left to drag.
• Nothing carries over. You re-buy from scratch every round while the budget rises, so each round is a fresh composition puzzle at a bigger scale.
• Losing a round costs a life (three by default). Out of lives means you are out, and you keep spectating. Last side standing takes the match.
• Multiplayer Arena is a 2 to 9 player free-for-all on one flat lobby list. Solo, you duel the house: a composed AI army built against the same budget and the same catalog rules.

Arena is composition poker. With buys hidden you are not countering what you see — you are guessing what the table will field and buying the answer, then adjusting round over round as the reads accumulate. The rising budget keeps early mistakes cheap and late ones decisive.