Two New Unit Types, Four Million Gold Coins, Black Hawk Arrow Tower (2)

First and foremost, these were used to purchase various rare resources.

For him, no amount of rare resources would ever be enough.

Starting from tier five units, recruiting any of them would require a substantial amount of rare resources. Basic resources like wood and clay were no longer relevant. 

For each tier five unit, even the less powerful ones, recruiting a single unit required at least a hundred units of rare resources. Take the Tyrant Azure Dragon, for example, which was considered a powerful tier five unit. Recruiting one required a staggering 2,400 units, equivalent to a minimum of a hundred thousand units when converted into regular resources. It was simply incomparable.

Apart from unit recruitment, Ji Chen's exclusive military talent tree was also a resource-consuming endeavor. Upgrading tier four units to tier five cost tens of thousands of rare resources, and advancing heroes was an even greater drain on resources.