Gen will be Jei's host eventuallyHe was injured by his blade, after all.
Originally, the series was going to be much shorter, with Usagi killing Lord Hikiji and possibly dying himself.Because of the saying that's tossed around a few times early on: A samurai cannot live under the same sky as the killer of his lord or father. Hikiji is both, though Usagi doesn't seem to know the latter (yet.)
Lord Hikiji is deformed.He is fully revealed only once in the whole series, and that's in front of Lord Hebi, his most trusted ally.
- I believe he's supposed to be the only human character.