I still remember reading the first issue of Teenage Mutant Ninja Turtles in German when I was 9 or 10 years old. In one of the panels where they first encounter the Shredder, I think Raphael says something like "Who is this guy? Darth Vader?". I had never seen Star Wars before and didn't even know how to pronounce the name. Still, a few days later I tried to be cool and dropped that reference at the playground. One of the older boys from the neighborhood was like "Who? 'Dart Fadder'? What are you talking about?" Naturally, they corrected my pronunciation, found it hilarious that I didn't know Star Wars and I was the idiot of the day. I never forgave Kevin Eastman for that and it took a few more years until I actually watched Star Wars and got the reference.
These days of course I know that having read the very first issue of TMNT at the age of 10 or so is actually several orders of magnitudes cooler than having seen Star Wars. ;)
Unfortunately not on PC but the Xenoblade Chronicles games are very MMO-like, in particular Xenoblade Chronicles X which puts less emphasis on the overall story and more on exploration, sidequests, levelling, min-maxing and gameplay systems. You'll find great worlds to explore and combat that is quite reminiscent of typical cool-down systems in MMOs. XBX does have some online components but you can play the whole game completely offline too.