Everyone knew that the Dwarfs had the War God's Chessboard, a magical relic built by the God of Forging. It had the ability to simulate various war scenarios, a miracle used for war game strategy and tactics.
Anyone who enters the relic and gets injured or killed, is immediately unharmed once the war game ends. Not only can battle experience be racked up, but the war game also has a playback function wherein one can grow rapidly by watching the playback and summarizing experiences gained and lost.
It was a divine artifact for any commander, allowing them to gain experience at a low cost. If they had to rely on actual battles to gain experience, the costs and consequences would be too severe; many talented commanders could be killed on the battlefield before they could rise through the ranks.
However, what no one knew was that the War God's Chessboard could no longer be activated.