I'm hoping Oda Nobunaga will be the main antagonist of the manga. He's one of the most interesting Japanese historical figures (I remember him ranking #1 in some polls), and sounds kind of like Sinbad+Kouen. I was wondering how Ohtaka is going to portray the likes of Oda, Toyotomi, Tokugawa, Ashikaga Yoshiaki...etc in a fantasy setting while being faithful to history. Then, I remembered that they turned the Shinsengumi into vampire-like creatures in Hakuouki, so maybe she can play around with it a bit.
I hope we'll also get to see Makara Naotaka
, the wielder of Taroutachi, a 221cm sword. Most of the most interesting people from the Sengoku period were dead when Miyamoto Musashi turned 15, so I hope this manga will only be loosely based on it with everyone being alive.
As for the blond guy, the Portuguese and I think the German did business with Japan at that time, so it's possible he's of European descent, or maybe we get a twist where he's half Japanese, half-European.