Board Thread:Spoilers!/@comment-26261400-20150902221427/@comment-24674051-20150903145621

Ok, Since I think we are getting Camelot and Arthur in the present, I highly doubt that Arthur was the king during Killian's Naval time, or even the king of the opposing kingdom.

As for relationship and look alikes, yes they have some similiarities, but I don't see that it would, could, or should mean that Killian and Arthur are related. Just my thoughts.