Agility is the attribute that grants armor and attack speed. For each point of agility a hero gets: 0.14 (1/7) Armor 1 Attack speed Additionally, agility heroes also get 1 attack damage per agility point.
Buildings are special units that are immune to most spells, use structure armor, and are immobile. Destroying a building rewards you with a bounty, similar to most creeps or heroes. Destroying towers rewards the entire