The military stats of all troop types can be upgraded in the Alchemical Laboratory.

The upgrade cost is initially the same for all troop types (spearmen, cavalry, ranged, knights, siege, and scouts). However, when one troop is upgraded, the cost for the other troop types is increased by one level.

For example, let's say you upgrade your knights. The cost for the other troop types will be increased to level 2. If you then upgrade your spearmen after that, the cost for the remaining troop types will be raised to level 3. And so on.

Think carefully about which troops to select first: upgrading them will be significantly cheaper.

Note: the higher the cost of the upgrade, the more Power and Hero's and Inquisitor's Experience each new upgrade will bring you.

By increasing the Alchemical Laboratory's level, you will be able to upgrade troops of a higher tier.