Okay, so I don't normally give feedback on comics that aren't my preferred genres, which this isn't, but I am familiar with the era of Japan that it's set in, so I thought it might be a good fit.
First off, I agree with @drawnbyyannan that the art is solid and you have good mood-setting happening. I lost track of exactly what was happening, but I think that was due to my own lack of exposure to action comics rather than an issue with the art or pacing. Attractive art is the first thing readers will notice, so strong start.
Moving on to the writing, Daimyo and Nobunaga didn't throw me, but I am the exception to the rule; most people outside of Japan won't be familiar with them. However, even knowing those two, I still didn't know who anyone was in the first episode (the one labelled 0). I figured out Hiro and the teacher in the second, so that was better.
My recommendation would be to remove any names from #0 other than Yasuke, since he seems important. Nobunaga can be "the ruler," Daimyo can be "warlords" or "powerful samurai," and the other character names (as well as Sengoku Jidai) can be removed entirely. Just keeping Yasuke will help the reader focus on him and remember him for #1. Sepuku might be okay - I think it's fairly well engrained in Western culture, and I understand why it was used. Still, an aside with the definition might be helpful.
In addition, a little extra proofreading would serve you well. I was a bit baffled by the change in font between the two episodes; the new font reads like everyone's yelling since we weren't introduced with an all-caps font. That said, capitalization in #0 was erratic. Nothing a little extra proofreading can't help!
All in all, I did enjoy the brief intro to Hiro and think he's set up well as the protagonist. I'd be interested to see how he does going forward, even if I don't necessarily care about what happens to Yasuke.
Best of luck!
