"And Aulë made the Dwarves even as they still are, because the forms of the Children who were to come were unclear to his mind, and because the power of Melkor was yet over the Earth; and he wished therefore that they should be strong and unyielding. But fearing that the other Valar might blame his work, he wrought in secret: and he made first the Seven Fathers of the Dwarves in a hall under the mountains in Middle-earth."
The Hall of Warriors is the main unit-producing structure for all three Dwarven factions. It can produce different units depending on the chosen faction. The unit types available for recruitment are swordsmen, pikemen, ranged, elite, and heroes. The Elite Equipment upgrade from the Dwarven Forge is required to recruit each faction's elite units and more powerful heroes, the Mineworker, and to research the Banner Carrier upgrade.
Worker's Tools: Upgrades the building to rank 2. At rank 2, economy buildings produce 25% more resources and gain 500 additional hit points. Recruitment buildings of the Dwarves work 20% faster and 1500 additional hit points
Forged Worker's Tools: Upgrades the building to rank 3. At rank 3, internal economy buildings produce 20% more resources and gain 1000 additional hit points. Recruitment buildings work 30% faster and 1500 additional hit points
The upgrades can be researched from the Dwarven Forge