Hanging up behind his torture rack is a Mythic Dawn banner. Looks exactly like the ones on the museum at Dawnstar.

Is this referenced anywhere? Like whether the castle formerly belonged to Mythic Dawn, or Harkon did.

Maybe Harkon is not really Harkon, and it's just an assumed name?

Maybe a Vampire just gave it to Harkon as a gift as they are rare nowdays.

You really think they Mythic dawn were the first to use that symbol? Please they've just lifted if from somewhere else because they liked the look of it. Look at the Nazi's and the swatziger or however you spell ot, most people think they invented it, however the aztecs or the myans used created it, i can remember which one. But the point of the matter is that that symbom probably has more to do with blocking out the sun than the Mythic dawn, i bet Harkon has had that think longer than all the members life spans combined.

I've already posted on this. Look on the other wall. Just opposite the banner there is a wall from the nordic Halls of Stories. Pretty cool, huh?

The swastika is a chinese character used in buddhist texts. Also used in others like Jainism and Hinduism, the symbol is still used to this day in the east. But off topic, I'll have to check those out in the castle, I don't think I noticed them.

Only Serana was put in a tomb for 4000+ years...who is to say Harkon wasn't a member of the Mythic Dawn during that time?

Molag Bal the patron of the Vampires supports domination and that is basically what the Mythic Dawn sought...that and personal paradise.

Nah I just think harkon is a collector I mean he has a werewolf pelt on display.

Harkon appears to be a devote follower of Molag Bol (sacrificing thousands of innocents, etc., to become a Vampire)
I highly doubt Molag Bol would approve of him joining a cult that worships Mehrunes Dagon.

lol.

Mehrunes Dagon hates vampires, and would kill them since they would make poor slaves.

As I said I think harkon is just a collector I mean its got a lot of stuff in his display cases.

They most likely barrowed it from the Indian symbol for good luck. The symbol is the same but the ends face the other direction.

Point taken about the banner but as this was a design made in the game someone put it there for a reason and it would be interesting to find out if it was laziness or if it was there with intent. It would be nice to know.

We all need to laugh sometimes.