I don’t have anything for this hero idea except for the weapon. They could wield a yari, which is a Japanese straight-headed spear (https://en.m.wikipedia.org/wiki/Yari). Typically, the blade can be anywhere between a few centimeters and a few feet long, but something around 2ft should be plenty. The shaft can also have various lengths; I’ve seen pictures of really long ones and others that are shorter. But so they’re not super similar to the Nobushi (with the extended reach), I’d probably use a shorter shaft. I couldn’t really find any pictures that wouldn’t make them look like Kensei or Orochi, so you’re going to have to use your imagination.