Preferably one on Steam. I used to play one a long time ago, it wasn't on Steam, but I can't remember the name of it either
Preferably a fantasy one, kill dragons and ogres and whatnot. Seeing as how I haven't played any RTS in a long time, I don't want one that is super hard. I can't think of any other pre-requirements, so if you want to ask anything or just throw out some suggestions, go for it. Thank you very much.
Edit: In hindsight, I wouldn't mind a modern/future one either. So really just any good RTS at this point.