Is this game like Ikarions "demonworld" or is this a game with base building like warcraft but with regiments?

I don't know how it was in demonworld, but base mechanics here... are quite simillar to ones in Disciples, to some point at least.
Basically - after the prologue, when you choose the faction, you can from world map access your castle. There you can purchase buildings and upgrades for your units, and of course creat an army. You can say that base is basically 'out of the way' - if you have funds, you can build there to your heart's content, nothing is rushing you, because the world map movements is turned based. And your base won't be attacked, as far as I remember.
So to have a chance you need to upgrade your town, but you don't send workers to do it - just pay up and it's done. If it's upgrading the 'builder' building you need to go back to main map and then come back.
Also - you don't gather resources like in other RTS games. Most income comes from missions, if you pick the right dialoge chocies sometimes (this is quite important mechanics in the game, choices made in dialouges).

Thanks for explaining the game!
sounds interesting, i will buy it. :)

The game can be harsh, I think it's also part of the charm. Good luck. ;)