Heroes and Lords can level up by gaining experience points, albeit a different process to Unit Experience, as well as acquiring new items, followers and banners. To raise an army, you first need a Lord, as what good is an army without a leader? Heroes are not available from Turn One of the campaign, but become unlocked when their specific building has been erected in a settlement their building requirements are shown on the Hero Recruitment panel. Heroes and Lords can be recruited on their respective recruitment panels, located on the Province Overview panel.
In this video you'll learn about the mighty Heroes and Lords at your disposal in Total War: WARHAMMER II