There is a series of fantasy strategy games that unites Spartan graphics, ultra-detailed mechanics and absolutely everything of myths, legends and fantasy lore into a single game: Dominions.
Currently at Dominions 6, it is the game for people who want to dig into fantasy warfare campaigns with micro- and macro-management and many opportunities for role playing.
Multiplayer mode and extensive mods (including randomized and a full-blown Forgotten Realms mod) on top of incredible customisation allow for incredible replayability. Sure, it is not an easy game to get into. But it tries to give lots of information on what is going on. Mostly.
If you enjoy old-school gaming and fantasy, give it a try.