Age of RPG is a data mod aimed at making RPG scenario design easier. By replacing several civilizations with "hero" options, selection from among six heroes and a tree of XP-based skills and feats are automatic without having to put triggers into each scenario. As a trade-off, the five buildsets remain as civs for classic RTS fun, with specialization into 17 of the original 18 civs after building a castle but no Imperial Age.
The main feature that's still missing is loot collection. Hopefully, I'll soon be able to make the hero collect gold from fallen enemies so the hiring system makes sense. For now, I recommend you just play with high resources.
The compressed file includes the mod itself (data and language files); guides for players, scenario designers, and modders; the Advanced Immobile Units AI by Zanzard Lothar (I think that's who made it), and a sample scenario for your enjoyment. The mod and scenario were made with UserPatch, but they both work with the CD version just as well.