The blacksmith will craft new powerful weapons for your warriors and train them to fight even harder. The Forge may be costly, but it will help on your journey to destroy everything! To command a successful army, you have to keep training your troops and make sure they keep improving. You can do that in the Forge.
A right amount of beer or nectar given to the blacksmith will result in more powerful weapons and training that can make them stronger, faster, or more resistant to enemies' attacks. Keep one thing in mind - every upgrade you complete makes the unit better, but also a little bit more expensive to recruit. But that's a small price for being unstoppable!
You get 2 Forges. You can even upgrade 2 Beer Troops or 2 Nectar Troops at the same time!
Orange - upgrades are completed.
Hour glassed - upgrades are actively upgrading.
Colored - upgrades are available.
Grey - upgrades are locked.
Heroes can not be upgraded in the Forge.
Related: Books crafted in the Hall of Ancestors can decrease Forge upgrade times.
Related: There are Forge related Missions to complete to win gems and Experience Points!