Although Fire Emblem 7 came out long before Harry Potter 7, for example, the relationship between Athos and Nergal in the former bears a striking resemblance to the relationship between Dumbledore and Grindelwald in the latter. Of course, the fact that FE7 came out first and there is no evidence that JKR plays video games means that this is probably just a coincidence.
Well, I can safely say that I don't remember the creator of the game ever saying that Athos was gay for Nergal, so the similarity might not be as apt there.
The same probably goes for Lyon in Fire Emblem 8, who also has quite a few similarities to Medivh in the Warcraft series: Innocent young men who become possessed by the Demon King, betray their friends, pretty much destroy their countries, and eventually get killed by their former friends. Granted, there are differences too; Lyon is an obvious case of the road to hell being paved with good intentions, but Medivh wasn't possessed through any fault or good intentions of his own. (It was his mother's good intentions that led to him becoming possessed.)
Well, his behavior is the case of a lot of villains. It's the "enemy that wants good by any circumstances" scenario.
In any case, I thought it was nice there was Hector and Durandal, though Hector had the wrong weapon. So I suppose that was just coincidence. It was the sword of Roland, however, so that much might not have been coincidence.